FI97552C - Paper-making strap and method for making it using differential light transmission technology - Google Patents

Abstract

A backside textured papermaking belt is disclosed which is comprised of a framework and a reinforcing structure. The framework has a first surface which defines the paper-contacting side of the belt, a second surface opposite the first surface, and conduits which extend between first and second surfaces of the belt. The first surface of the framework has a paper side network formed therein which defines the conduits. The second surface of the framework has a backside network with passageways that provide surface texture irregularities in the backside network. The papermaking belt is made by applying a coating of photosensitive resinous material to a reinforcing structure which has opaque portions, and then exposing the photosensitive resinous material to light of an activating wavelength through a mask which has transparent and opaque regions and also through the reinforcing structure. A process for making paper products is also disclosed which involves applying a fluid pressure differential from a vacuum source through the belt to a partially-formed embryonic web of papermaking fibers. The fibers in the embryonic web are deflected into the conduits of the papermaking belt by the vacuum pressure while the papermaking belt and the embryonic web travel over the vacuum source. Following the deflection, the paper web is impressed with the paper side network of the belt, and dried to form the final product.

Description

- 97552

Papermaking belt and method of making it using differential light transmission technique

FIELD OF THE INVENTION This invention relates generally to papermaking belts useful in paper machines for making strong, soft, absorbent paper products. The present invention also relates to a method of making such a papermaking belt and to papermaking methods using such belts. More specifically, the present invention relates to papermaking belts consisting of a resin lattice and a reinforcing structure having a texture on the side in contact with the machine, i.e. the back side. The texture is formed on the belt by applying a coating of a light-sensitive resin material to a reinforcing structure having opaque portions, and then exposing the resin material with light having an activating wavelength through the reinforcing structure so that the opaque material of the reinforcing structure is opaque. The uncured resin is then removed, leaving passageways on the back of the belt.

Background of the Invention 25 One of the predominant features of daily life in modern industrialized societies is the use of paper products for various purposes. Paper towels, face papers, toilet paper, etc. are in almost constant use. The high demand for such papers has created the need for 30 improved product versions and their manufacturing methods. Despite major advances in papermaking, research and development continues to aim to improve both products and their manufacturing methods.

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Paper products such as paper towels, facial papers, toilet paper, etc. are made from one or more tissue webs. If the products are to fulfill their function and gain widespread acceptance, the webs of tissue-5 from which they are made must have certain characteristic physical characteristics. The most important of these properties are strength, softness and absorbency.

Strength is the ability of paper to maintain its physical integrity during use.

Softness is a pleasant sensation that is observed when paper is squeezed in the hand and used for its purposes.

Absorbency is a property of paper that allows it to receive and retain fluids, especially water and aqueous solutions and suspensions. When assessing the absorbency of a paper, not only the absolute amount of liquid retained by a particular amount of paper is significant, but also the rate at which the paper absorbs the liquid-20. In addition, when the paper is formed into a product such as a towel or rag, the ability of the paper to cause liquid to enter the paper and thus leave a dry wiped surface is important.

In methods of making paper products for use in tissue, towel, and sanitary products, an aqueous slurry of paper fibers is generally prepared and then dewatered from the slurry while rearranging the fibers in the slurry to form a paper web. Different types of equipment can be used to aid in the dewatering process.

Today, most manufacturing processes use machines known as either flat wire machines or double (flat) wire machines. In flat wire machines, the paper slurry is fed to the upper surface of a moving endless belt, which belt 35 serves as the initial forming surface of the machine. In the double wire machines 97552 3, the slurry is sandwiched between two converging flat wires, where the initial dewatering and rearrangement of the papermaking process is carried out.

After the initial formation of the paper web with the flat wire 5a or wires, each type of machine generally conveys the paper web through the drying process or processes on another fabric in the form of an endless belt, which is often different from the flat wire or wires. This second fabric is sometimes called a drying fabric. Numerous arrangements of one or more flat wires and one or more drying fabrics, as well as one or more drying processes, have been used successfully and to some extent less successfully. In one or more drying processes, mechanical compression of the paper web, vacuum dewatering, drying by blowing heated air through the paper web, and other types of procedures may be performed.

As can be seen from the above, papermaking belts or fabrics have different names according to their intended use. Flat wires, also called Four-drinier belts, forming wires, or forming fabrics are tools used in the initial forming zone of a paper machine. As mentioned above, drying fabrics are fabrics that carry a paper web through a drying operation of a paper machine. Many other types of straps and fabrics are also possible. Most previously used papermaking fabrics usually consist of a piece of woven fabric with the ends joined together by a seam to form an endless belt. Woven papermaking fabrics generally comprise a plurality of detached longitudinal warp yarns and a plurality of detached transverse weft yarns woven together in a particular weave pattern. Previous belts have included fabrics comprising a single layer (consisting of warp and weft yarns), multilayer fabrics, and fabrics having a few layers, each comprising interwoven warp and weft yarns. Initially, papermaker's yarns were made from metal yarns consisting of materials such as phosphor-5 bronze, bronze, stainless steel, brass, or combinations thereof. Often different materials were placed on and attached to the fabrics in an effort to make dewatering more efficient. Recently, it has been found in the papermaking industry that synthetic materials can be used, in whole or in part, to form the underlying wire structures of better quality than forming wires made of metal wires. Such synthetic materials have been nylon, polyesters, acrylic fibers and copolymers. 15 Although many different methods, fabrics, and arrangements of these fabrics have been used, only some of these methods, fabrics, and fabric arrangements have resulted in commercially successful paper products.

One example of paper webs widely accepted by the consuming public are webs made by the method described in U.S. Patent 3,301,746 (Sanford and Sisson, January 31, 1967). Other widely accepted paper products are prepared by the method described in U.S. Patent 3,994,771 (Morgan and Rich, November 30, 1976). However, despite the high quality of the products produced by these methods, the search for even better products has continued, as mentioned above.

One commercially significant improvement to the aforementioned paper webs was made by the method described in U.S. Patent 4,529,480 (Trokhan, July 16, 1985), which is incorporated herein by reference. This improvement included the use of a papermaking belt (referred to as a "guide portion") consisting of a porous woven portion surrounded by a cured crosslinked resin made of a photosensitive resin. The resin grid was provided with several separate channels known as "control channels". The method in which this guide member was used included, among other steps, contacting the paper fiber primary web with the top surface of the guide member and directing a suction pressure or other fluid pressure difference to the web from the back (machine contact side) of the guide member. The papermaking belt used in this method was called a "guide section" because the paper fibers are guided 10 and arranged in the guide channels of the cured resin lattice during the use of the liquid pressure difference. Using the above-mentioned improved papermaking method, it was finally possible to form a paper having certain desired preselected properties, as mentioned below.

The guide described in the aforementioned Trokhan patent was fabricated by the method described in U.S. Patent 4,514,345 (Johnson et al.), Which is incorporated herein by reference. Johnson et al. the method described in the patent includes the following steps: 1) coating the porous woven element with a photosensitive resin; 2) adjusting the thickness of the photosensitive resin to a preselected value; 3) treating the resin with light having an activating wavelength through a mask containing opaque and transparent areas, and 4) removing the uncured resin. This method resulted in a guide portion having a grid having a surface in contact with the paper web and a surface in contact with the machine, both of which were provided with a network pattern surrounding the channels that was substantially planar or smooth.

Paper made by the method described in U.S. Patent No. 4,529,480 is described in U.S. Patent No. 4,637,859 to Trokhan, which is incorporated herein by reference. It is characteristic of this paper 35 that it has two physically distinct areas distributed on its 6 5ΓΕ52 surfaces. One of the regions is a continuous network region with a relatively high density and high specific strength. The second area is an area consisting of numerous domes completely surrounded by a network area.

The images in the latter area have a relatively low density and a relatively low specificity compared to the network area.

The paper made by the method described in U.S. Patent No. 4,529,480 was actually stronger, softer and more absorbent than the paper made by the previous methods due to a few factors. The strength of the produced paper improved as a result of the relatively high specific strength provided by the network area. The softness of the paper produced increased as a result of the formation of numerous domes with an odor of 15 to 15 on the surface of the paper. The absolute amount of liquid retained by the paper (one of the determinants of the absorbency of the paper) increased due to a decrease in the overall density of the paper.

Although the above-mentioned improved method worked quite well, it has been found that when the above-mentioned method-. If the control part of the system passes over a vacuum device used for dewatering in the papermaking process, certain undesirable events occur. Of most concern was the large number of partially dewatered fibers in the paper web passing completely through the guide section. This led to the undesirable result that fairly mobile paper fibers clog the vacuum machinery used for dewatering. Another undesirable phenomenon was the tendency of these moving paper fibers to accumulate in the dewatering machinery to the extent that fiber clumps formed in the machinery. This accumulation of fibers caused wrinkles and creases, especially longitudinal folds, to form in the previous papermaking belts as the belts repeatedly passed over the dewatering strip during the papermaking process. catastrophic failure.

The importance of the difficulties experienced with these previous belts was compounded by the relatively high price of the belts. In most cases, the manufacture of the porous woven element incorporated into these belts required (and still requires) expensive textile processing operations, including the use of large and expensive weaving machines. These woven elements also include considerable amounts of relatively expensive filaments. Belt costs continue to increase when heat-resistant filaments are used, which is generally necessary in the case of belts passing through a drying operation.

15 In addition to the cost of the belt itself, the failure of the papermaking belt also has a serious impact on the efficiency of the papermaking process. Frequent paper machine belt failures can have a significant effect on the economics of papermaking operations due to the high utilization losses of papermaking machinery (i.e.,

due to the "downtime" of the machine) during the time the replacement belt is installed on the paper machine.

During the development of the papermaking method described in U.S. Patent No. 4,529,480, it was assumed that the network formed on the lower surface (machine contact surface) of the resin grid had to be substantially planar to achieve the desired abruptness of suction pressure orientation required to guide and rearrange fibers in improved guide channels. 30 to form dome areas on paper.

Without wishing to be bound by any theory, it is now believed that the problems encountered with previous papermaking belts with smooth backgrounds may have been due, at least in part, to the extremely abrupt application of suction pressure to the paper web as it passes over the dewatering machine. It is assumed that previous papermaking prices with a smooth background actually formed a temporary barrier over the vacuum source. When the open channels (guide channels) of the previous type of papermaking belt were then approached, the suction pressure was applied to the water-loaded, highly mobile fibers of the fibrous web on top of the resin grid extremely abruptly. The sudden effect of this suction pressure on the assumption was caused by the sudden guiding of the moving fibers, which has been sufficient to allow them to pass completely through the papermaking belt. It is also hypothesized that this sudden effect of suction pressure and fiber migration causes very small holes in the dome areas of the finished paper, which are undesirable in some, but not all, cat-15 cases.

One theory regarding the excessive accumulation of paper fibers on the surfaces of vacuum dewatering equipment is that previous papermaking belts with a smooth background did not have sufficient surface texture on the back side. It is assumed that a certain amount of surface texture is necessary for such resin-coated belts to be able to remove the paper fibers accumulating on the vacuum dewatering apparatus through the abrasive action of the belt passing over the vacuum dewatering apparatus.

As a result of the above, there is a need for an improved papermaking process that is not hindered by the undesired accumulation of these moving paper fibers in the vacuum dewatering machinery used in the process. Therefore, there is also a need to achieve t.

30 is an improved papermaking belt and a method of making the same which eliminates the above-mentioned problems caused by the use of a papermaking belt made by previous methods.

Therefore, it is an object of the present invention to provide an improved papermaking method in which 9

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substantially eliminating or eliminating the migration of the above-mentioned moving paper fibers.

It is also an object of the present invention to provide a papermaking belt which substantially reduces the problem associated with prior resin coated papermaking belts regarding the accumulation of paper fibers in a vacuum dewatering machine.

Another object of the present invention is to reduce the creasing of papermaking belts and subsequent breakage caused by the accumulation of paper fibers on the surface of the vacuum dewatering machinery used in the papermaking process.

It is also an object of the present invention to provide a papermaking process which results in the elimination of small holes 15 in the dome areas of the finished paper web (unless such holes are a desirable feature of the paper being produced).

It is also an object of the present invention to provide a papermaking belt having passageways which form surface texture irregularities on the back side of the belt, and a method of making this passageway in which these passageways can be formed on the belt without sacrificing the strength of the entire papermaking belt.

It is a further object of the present invention to provide a papermaking belt having a longer service life when used in the papermaking process of the present invention than prior papermaking belts, and an economically viable method of making this papermaking belt.

These and other objects of the present invention will become more apparent from the following description and the accompanying drawings.

SUMMARY OF THE INVENTION The textured 35 papermaking belt of the present invention generally consists of two main elements, a lattice, and a reinforcing structure. When the papermaking belt of the present invention in a preferred form, it is an endless belt having a paper-contacting side and a textured back side 5, which is in contact with the paper side of the opposite side and in contact with the papermaking machinery used in the process. The grid is preferably a cured polymeric, photosensitive resin grid having a first surface defining a surface in contact with the paper of the belt and a second surface opposite the first surface and channels passing between the first and second surfaces. the first surface of the grid is formed by a paper-side network, which surrounds and defines the openings in the channels. 15 The second surface of the net defines at least a portion of the textured back side of the strap. the second surface of the grid is a backside network with a distinctive channels of roads. These passages form a pintatekstuuriepäsään-homogeneities of the second surface of the backside network. The reinforcing structure is placed between the first surface of the lattice and at least a part of the second surface of the network, and its function is to reinforce the lattice. The reinforcing structure has a paper-facing side and from the machine towards the incoming side of the paper-finish side of the opposite side. 25 The reinforcing structure also has pores and a reinforcing component consisting of a plurality of structural components. The first part of the reinforcing component has a first opacity, and the second part of the reinforcing component has a second opacity which is lower than the first opacity. The first opacity is sufficient to substantially prevent curing of the lattice-forming photosensitive resin material when the photosensitive resin material is in its uncured state and a first portion of the reinforcing component is interposed between the photosensitive resin-35 material and the actinic light source. The second opacity is such that it allows the photosensitive resin material to cure. In addition, the first part determines the projection of the first surface. Background of the grid-side network of passageways position with respect to the reinforcing structure 5 is such, that the routes are mainly located on the first surface of the projection.

A method of making a papermaking belt according to the present invention comprises the steps of: (a) providing a forming unit having a work surface; (B) providing a reinforcing structure having the paper-facing side, of the machine-facing side of the paper-facing side opposed to the side pores and a reinforcing component which is composed of a plurality of structural components 15 of the first portion of the reinforcing component has a first opacity and a second portion of the reinforcing component has a second an opacity lower than the first opacity, the first opacity is sufficient to substantially prevent curing of the lattice-20 sensitive resin material forming the lattice when the photosensitive resin material is in its uncured state and the first portion of the reinforcing component is placed in the second photosensitive resin material and actinic the opacity is such as to allow the light-sensitive resin material to cure, and the first part determines the projection of the first surface; (c) contacting at least a portion of the side of the reinforcing structure facing the machine with the work surface of the forming unit; (D) applying a liquid photosensitive resin coating to at least one side of the reinforcing structure such that the coating forms a first surface and a second surface and is distributed so that at least a portion of the second surface of the coating is located adjacent the working surface of the forming unit; the surface is interposed between the first part of the reinforcing component and the working surface of the forming unit, and the paper-facing side of the reinforcing structure is interposed between the first and second surfaces 5 of the coating and the part of the coating interposed between the first surface and the paper-facing surface of the reinforcing structure forms resin loads; (e) adjusting the thickness of the overload to a preselected value; (F) providing a mask having opaque and transparent areas, wherein the opaque areas, together with the transparent areas, define a preselected pattern in the mask; (g) placing a mask between the liquid photosensitive resin coating and the actinic light source so that the mask is in contact with the first surface of the coating, the opaque areas of the mask protecting a portion of the coating from light beams emitted by the light source and leaving the transparent areas (h) curing the unshaded portions of the liquid photosensitive resin coating and those portions of the coating that are allowed to cure by the second portion of the reinforcing structure and not curing the shaded portions and those coating portions located between the first portion of the reinforcing structure and the forming unit working surface coating with light having an activating wavelength from the light source through the mask and reinforcing structure to form a partially formed composite belt, and (i) removing the uncured liquid photosensitive resin from the substantially partially formed composite belt, leaving the cured resin siristikko having a plurality of channels in areas that are mass-13 97 552 also opaque regions are protected from said light rays by, and paths that form a grid in the backside network pin irregularities in the texture corresponding to those parts of the second surface of the coating which have been prevented by the first part of the reinforcing structure from hardening.

The method of making a strong, soft, absorbent paper web of the present invention comprises the steps of: (a) providing an aqueous dispersion of paper fibers; 5 (b) forming the paper fiber primary web from the dispersion by hand on a porous surface; (C) contacting the embryonic web into contact with the papermaking belt of the present invention, the paper coming into contact with the sides; (D) conveying the papermaking belt and the primary web over the vacuum source and directing the liquid pressure difference to the primary web by the vacuum source so that the liquid pressure difference is provided from the rear side of the papermaking belt through the papermaking belt channels, ai-15. at least a portion of the paper fibers in the primary web are directed into the channels of the papermaking belt and water is removed from the primary web through these channels and the paper fibers in the primary web are rearranged to form an intermediate web of paper fibers under conditions such as deflection at the latest; (e) printing the web on the paper side into the intermediate product web by placing an intermediate product web between the papermaking belt and the printing surface to form an interest-compressed paper fiber web, and (f) drying the interest-compressed web.

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Brief description of the drawings

Figure 1 is a schematic representation of one embodiment of a continuous paper machine useful in carrying out the method of the present invention.

Fig. 1A is a simplified cross-sectional view showing a partially formed paper-fiber primary web prior to being guided into the channel of a papermaking belt according to the present invention.

Fig. 1B is a simplified cross-sectional view 10 of a portion of the primary web shown in Fig. 1A after the fibers of the primary web have been guided into one of the channels of the papermaking belt.

Figure 2 is a top view of a portion of a preferred embodiment of an improved papermaking belt in accordance with the present invention.

Fig. 3 is an enlarged cross-sectional view of a portion of the papermaking belt shown in Fig. 2 taken along line 3-3.

Fig. 4 is an enlarged cross-sectional view of a portion of the papermaking belt shown in Fig. 2 20 taken along line 4-4.

Figure 5 is a top plan view of a portion of an alternative embodiment of a papermaking belt according to the present invention having a single ply reinforcing structure.

Fig. 5A is a cross-sectional view of a portion of the papermaking belt shown in Fig. 5 taken along line 5A-5A.

Fig. 5B is a cross-sectional view of a portion of the papermaking belt 30 shown in Fig. 5 taken along line 5B-5B

along.

Figure 6 is an enlarged and top view of one preferred woven multilayer reinforcing structure that may be used in the papermaking belt of the present invention.

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Fig. 7 is an enlarged sectional view of the reinforcing structure shown in Fig. 6 taken along line 7-7 of Fig. 6.

Fig. 8 is an enlarged sectional view of the present reinforcing structure of Fig. 6 taken along line 8-8 of Fig. 6.

Fig. 9 is an enlarged sectional view of the reinforcing structure shown in Fig. 6 taken along line 9-9 of Fig. 6.

Fig. 10 is an enlarged sectional view of the reinforcing structure shown in Fig. 6 taken along line 10-10 of Fig. 6.

Fig. 11 is an enlarged sectional view of the reinforcing structure shown in Fig. 6 taken along line 11-11 of Fig. 6.

Figure 11A is a sectional view of the eight pattern, however, which also shows part of the surrounding framework, which illustrates the context of the present invention is useful in one type of woven reinforcing structure of the variant in which the bottom side of the warp yarns 20 are opaque.

-Figure 11A, 11B is a sectional view of a pattern, which illustrates a single type of woven reinforcing structure of a second variation, wherein the second bottom-side warp yarn is opaque.

Fig. 11C is a top plan view similar to Fig. 6 illustrating another variation of one type of woven reinforcing structure useful in the present invention, in which a pattern is printed on the surface of the reinforcing structure with an opaque material.

Figure 12 is a top plan view of a portion of the reinforcing structure with a portion of the surrounding lattice in place around the reinforcing structure.

Fig. 12A is a side view of a portion of the reinforcing structure of Fig. 12 illustrating the position of some passageways and surface texture irregularities with respect to a few projections of the surface of the reinforcing structure.

Fig. 13 is a top view, similar to Fig. 6, of the reinforcing structure illustrating the projection of the reinforcing surface of a portion of the reinforcing structure.

Fig. 14 is another view similar to Fig. 13 of a similar reinforcing structure seen from above, illustrating some projections of the warp surfaces of the reinforcing structure.

Fig. 15 is a side view similar to Fig. 8 of a reinforcing structure illustrating the projections of the warp surfaces shown in Fig. 14 seen from another angle.

Fig. 16 is a plan view similar to Figs. 13 and 14 of the reinforcing structure, illustrating some projections of the weft surfaces of the reinforcing structure.

Fig. 17 is an enlarged sectional view similar to Fig. 7 illustrating the projections of the tissue surfaces shown in Fig. 16 as viewed from another angle.

Fig. 18A is a plan view, similar to the previous top 20 views, of the reinforcing structure, illustrating some projections of the knee regions of the reinforcing structure.

Fig. 18B is an enlarged side view, similar to Fig. 7, of a reinforcing structure illuminating some projections of the knee areas of the reinforcing structure as seen from another angle.

Fig. 18C is an enlarged side view, similar to Fig. 8, of the reinforcing structure illustrating some projections of the knee regions of the reinforcing structure as viewed from another 30 angle.

Fig. 19 is an enlarged schematic view of one preferred channel opening shape in connection with a papermaking belt according to the present invention.

Figs. 19A and 19B are a top plan view of the projection of the first surface of the lattice area of the grid of the papermaking belt shown in Figs.

Figure 20 is an enlarged schematic view of another preferred shape of the channel opening.

5 Figure 21 is a greatly enlarged and exaggerated schematic sectional view of a portion of the papermaking belt and a reinforcing grid structure, which shows details of the passageways and surface texture irregularities in the backside.

Figures 22A, B and C are simplified schematic diagrams of various types of background textures that may occur on a papermaking belt.

Fig. 22D is a greatly enlarged view of a portion of a reinforcing component as shown in Figs. 22A to 22C, showing some elevated portions of the reinforcing component.

Fig. 23A is an enlarged schematic diagram of the problems encountered when a papermaking belt without the improvements disclosed herein encountered during the papermaking process of a vacuum dewatering apparatus.

Fig. 23B is an enlarged diagrammatic view of the manner in which the papermaking belt of the present invention alleviates previously encountered problems.

Fig. 24 is a graph illustrating the application of suction pressure to both a papermaking belt with and without a background texture disclosed herein.

Fig. 25 is a schematic representation of a basic apparatus for manufacturing a papermaking belt according to the present invention.

Fig. 26 is an enlarged schematic view of the post-curing unit of the apparatus shown in Fig. 25.

Fig. 27 is an enlarged schematic diagram of a method of manufacturing a papermaking belt according to the present invention by casting a photosensitive resin on a woven multilayer reinforcing structure having opaque yarns.

Fig. 28 is an enlarged schematic sectional view taken along line 28-28 of Fig. 27 showing 5 parts of the casting surface and those parts of the photosensitive resin which do not cure, thereby forming surface texture irregularities on the back side of the papermaking belt according to the present invention.

Fig. 29 is an enlarged schematic sectional view of the casting surface shown in Fig. 27, generally similar to Fig. 28, showing one alternative embodiment of the reinforcing structure shown in Fig. 28.

Figure 30 shows a schematic top view of a portion of the testing apparatus which is used in measurements 15 air leakage of the paper-manufacturing belt of the present invention, the back side of the cross.

Fig. 31 is a side schematic view of the test apparatus shown in Fig. 31.

Fig. 32 is a graphical representation of the calibration of a flow meter used in the two apparatus shown in the previous 20 figures.

Fig. 33A is a top plan view, approximately 25 times magnified, of the papermaking belt above the improvements shown herein.

Fig. 33B is a top plan view, approximately 25 times magnified, of the back of a papermaking belt without the improvements disclosed herein.

Fig. 34A is a photograph magnified approximately 25 times above a papermaking belt made in accordance with the present invention. The image is taken at an angle of about 35 degrees to the imaginary normal of the upper surface.

Fig. 34B is a photograph approximately 25 times magnified from the background of the papermaking belt shown in Fig. 34A. The image is taken at an angle of about 35 degrees to the imaginary normal of the background-35 surface.

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Fig. 34C is a transverse photograph of the papermaking belt shown in Figs. 34A and 34B taken approximately 25 times.

Detailed description of the invention

The description includes the following parts in the order listed: a detailed description of the papermaking belt of the present invention, a method of making this papermaking belt, and a detailed description of the method of making the paper of the present invention.

1. Papermaking belt

In a typical paper machine illustrated in Figure 1, the papermaking belt of the present invention is in the form of an endless belt, the papermaking belt 10. 1, the papermaking belt 10 carries paperirai-edge (or "fiber web") in its various forming stages and passing the arrow B in a direction of the papermaking belt 15 return rolls 19a, 19b, painojättötelan 20, papermaking belt return rolls 19c, 19d, 19e and 19f, and emul-sionlevitystelan 21 above. The loop rotated by the papermaking belt 10 includes means for applying a liquid pressure difference to the paper web, such as a vacuum catcher 24a and a multi-slot suction box 24. In Figure 1, the papermaking belt also passes through a pre-dryer such as a blow dryer 28 and a jet roll 20 .

Although the preferred embodiment of the present invention is in the form of an endless belt, the present invention can be incorporated into a variety of other forms, including, for example, stationary sheets for use in making handmade sheets or rotating cylinders for use in other types of continuous processes. Regardless of the physical shape, the papermaking belt 10 generally has certain physical properties.

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The general characteristics of the papermaking belt are shown in Figures 2-4. The papermaking belt (i.e., simply "belt") 10 of the present invention generally consists of two main elements: a lattice 32 5 (preferably a hardened polymeric photosensitive resin lattice) and a reinforcing structure 33. When the papermaking belt is an endless belt, it generally has two opposite sides. , referred to herein as the paper-contacting side 11 and the textured backing side, i.e. simply the backing side 12. The backing side 12 of the belt 10 is in contact with a papermaking machine such as a vacuum catcher 24a and a multi-slit suction box 24. The grid 32 has a first surface 34, a second pin 15 opposite the first surface 34 and passages 36 between the first surface 34 and the second surface 35. The first surface 34 of the grid 32 is in contact with the fibrous webs to be dewatered and defines in contact with the side 11 of the belt.

Channels 36 extending between the first surface 34 and the second surface 35 conduct water from the fibrous webs resting on the first surface 34 to the second surface 35 and provide areas where the fibers of the fibrous web can be directed and rearranged. Figure 2 shows that the network 32a includes a fixed portion of the grid 32 surrounding the channels 36 and defines a network-like pattern. As shown in Figure 2, the openings 42 of the channels 36 are arranged in the network 32a according to a preselected pattern. Figure 2 shows that a paper-side network 34a is formed on the first surface 34 of the lattice 32, which surrounds and defines the openings of the channels 36 in the first surface 34 of the lattice 32. As will be shown in Figure 34B, the framework 32 to the second surface 35 has a backside network 35a which surrounds and defines 32 in the second surface 35 of the framework of the chicken-35 of the 36 apertures 43. Figures 3 and 4 show that this - paperlnvalmlstushlhnan of the 97 552 21 10 of the invention the reinforcing the structure 33 is generally shown to be at least partially surrounded by (or embedded in or enclosed in) the lattice 32. More specifically defined by the reinforcing structure 33 is positioned between 34 and 32 at least a portion of the first surface 5 of the framework 32 to the second surface of the grid 35. Figures 3 and 4 also show that the reinforcing structure 33 has a paper-facing side 51 and a machine-facing side 52 of each of the paper side 51 the opposite side. As shown in Fig. 2 10, the reinforcing structure 33 has pores 39 and a reinforcing component 40. The reinforcing component 40 comprises portions of the reinforcing structure other than the pores 39 (i.e., an integral part of the reinforcing structure 33). The reinforcing component 40 generally consists of a plurality of structural components 15a. The reinforcing structure 33 has a projection of the open surface determined by the projection of the surfaces defined by the pores 30 and a projection of the reinforcing surface determined by the projection of the reinforcing component 40. Figures 3 and 4 show that the second surface 32 of the grid 35 is taustapuo-20 gum network 35a with a plurality of passageways 37 that provide surface texture irregularities in the network 38 of the framework 32 to the backside 35a. The passageways 37 are different paths than the channels 36 passing between the first surface 34 and the second surface 35 of the truss 32. The passageways 25 37 allow air to pass between the back surface 12 of the papermaking belt 10 and the surfaces of the vacuum dewatering equipment used in the papermaking process (such as vacuum trap 24a and suction box 24) when the dewatering equipment with the machinery used.

The side 11 of the belt 10 shown in Figures 1-4 in contact with the paper is the surface of the papermaking belt 10 97552 22 which is in contact with the paper web to be dewatered and rearranged into a finished product. As shown in Fig. 1, the side of the belt 10 called the side 10 in contact with the paper is called by this name, even if it carries the paper web only in a part of each turn in the paper machine. The side of the belt 10 referred to as the paper contacting side 11 is also consistently referred to by that name, although it may temporarily come into contact with the machinery used in the papermaking process at some part of each turn (such as the papermaking belt return roll 19d). The paper-contacting side 11 of the belt 10 may also be referred to as the "top surface" or "surface-contacting surface" of the belt 10. It is to be understood that, although the belt 10 with the paper-contacting side 11 may be referred to as the upper surface may be in contact with the side 11 be such that it is facing downwardly on the return path 20 in a papermaking machine when the belt 10 is in the form of an endless belt. As shown in Figures 2-4, the paper contact side 11 of the belt 10 is generally formed entirely of the first surface 34 of the grid 32.

As shown in Figure 1, the opposite surface of the belt 10, the backside 12, is a surface that passes over papermaking machinery used in the papermaking process, such as papermaking belt return rollers 19a-19c, 19e and 19f and vacuum catch 24a and suction box 24, as well as other drawings missing from drawings. and is generally in contact with it. Figure 1 shows that the side of the belt 10, referred to as the backsheet 12, is referred to by this name, although it may occasionally deflect away from the machinery used in the papermaking process (such as at the papermaking belt return roll 19d). However, the back side 12 is separable from the paper contacting side 11 because the back side 12 el never comes into contact with the paper barrel during the papermaking-5 process. The backside 12 of the papermaking belt of the present invention may also be referred to herein as the "bottom surface" of the belt. It may also be referred to as the "wear surface" of the belt because it is the surface of the belt subjected to abrasion repeatedly over the papermaking process. . it should be understood that, although the belt 10 backside 12 may be referred to as the bottom surface, the backside 12 of the orientation to be such that it is facing upward on the return-path in a papermaking machine when the belt 10 is in the form of an endless 15 of the belt. In general, comprising a framework and a reinforcing structure of the belt taustapuoll 12 may be all of the framework 32 of the backside network 35a formed, although such an embodiment may not occur often not according to the present invention paperinvalmistushihnas-20 portion 10. Alternatively, the backside 12 may be formed for the machine 33 of the reinforcing structure 52 on behalf of the future, or may consist in part of the second surface 35 of the lattice 32 and in part of the reinforcing structure 33 facing the machine side 52. It is this bottom surface, i.e. the back side 12, and methods for forming pathways and surface texture irregularities therein are of primary importance in the present invention.

Figures 2-4 show a reinforcing structure 33, one of the main elements of the papermaking belt 10 30 of the present invention. The reinforcing structure 33 reinforces the resin grid 32 and has a suitable open projection surface to allow the vacuum dewatering machinery used in the papermaking process to adequately perform its function of removing water from the partially formed paper webs and allowing the water removed from the paper web to pass through the papermaking web. The reinforcing structure 33 can take any of a variety of forms. The reinforcing structure 33 may comprise a woven element (sometimes also referred to herein as a woven "fabric"), a nonwoven element 5, a wire, a mesh (e.g., a thermoplastic mesh material), a gauze or strip or sheet (made of metal, plastic, or other suitable material) having punched or drilled a plurality of holes, provided that the reinforcing structure 33 10 sufficiently reinforces the lattice 32 and has a sufficient open projection surface for the purposes defined above. The reinforcing structure 33 preferably comprises a woven element (or more specifically a porous woven element), such as the element shown in Figures 2-4.

As shown in Figures 2-4, the reinforcing structure 33 generally comprises a reinforcing component 40 and a plurality of pores (i.e., "small holes") 39. The reinforcing component 40 is a portion of the reinforcing structure other than the pores 39. That is, the reinforcing component 40 is 33 fixed part. The reinforcing component 40 consists of one or more structural components 40a. As used herein, the term "structural components" refers to the individual structural elements that make up the reinforcing structure 33.

The pores 39 allow fluids (such as water removed from the paper web) to pass through the belt 10. The pores 39 form one of the aperture groups of the papermaking belt 10. Figure 2 shows that the pores 39 may form a pattern on the reinforcing structure 33. However, the pattern formed by the pores 39 30 must be distinguished from a prefabricated pattern formed by channel openings, such as first channel openings 42. Figure 2 shows that the size of each pore 39 is typically only a fraction of the size of the channel opening 42, but the opposite ratio is also possible.

- 97552 25

As shown in Figures 3 and 4, the reinforcing structure 33 has two sides. These are the paper-facing side (or the "paper support side"), generally designated by the numeral 51 and faces the fiber webs which have 5 to be dewatered, and the paper-facing side toward the opposite side of the machine-facing side (or "in contact with the rolls half "), generally numbered 52 and oriented towards the papermaking machinery. The sides 10 of the reinforcing structure 33, referred to herein as the paper-facing side 51 and the machine-facing side 52, are referred to by these names, although short periods may occur during each revolution of the papermaking belt 10, in which case they may be in the opposite orientation. In addition, these names are consistently used on the respective sides of the reinforcing structure 33 even before the reinforcing structure 33 is incorporated into the papermaking belt 10 of the present invention and the belt 10 is installed in the paper machine. Thus, the side of the reinforcing structure 33 called the machine-facing side 52 in the method of making the papermaking belt 10 of the present invention is the side that is generally oriented toward the papermaking machine when the finished belt is mounted on the papermaking machine. The paper-facing side 51 is always on the opposite side 25 to the machine-facing side 52. As shown in Figures 3 and 4, the reinforcing structure 33 is placed between the first surface 34 of the lattice 32 and at least a portion of the second surface 35 of the lattice 32.

Figures 2-4 show that when the reinforcing structure 30 33 comprises a woven element, the individual yarns woven together into a woven element form the structural components 40a of the reinforcing structure 33. If the reinforcing structure 33 comprised a nonwoven element, the individual fibers that make up the nonwoven element would form the structural components 40a. In either case 97552 26 there are a plurality of structural components such that the lime these structural components 40a together form a reinforcing component 40. If the reinforcing structure 33 is on the other hand a plate in which a plurality of holes are stamped, there is only one structural component 40a 40.

The structural components 40a of the woven reinforcing structure comprise yarns, filaments, filaments or fibers. It is to be understood that the terms yarns, strands, filaments, and strands are synonymous when used to describe the structural components 40a of a woven reinforcing structure. It is also to be understood that the above terms (yarns, threads, etc.) include not only monofilament elements but also multifilament elements.

When the reinforcing structure 33 comprises a woven element, as shown in Figures 2-4, some of the individual structural components are machine direction warp yarns, generally designated 53, and some transverse weft yarns, generally designated 54. As used herein, the terms " "machine direction warp", "warp" and "support warp" are synonymous and refer to yarns that are generally oriented in the machine direction when the papermaking belt 10 of the present invention is mounted on a paper machine. As used herein, the terms "transverse weft", "weft", "wire weft" and "warp balancing weft" are synonymous and refer to yarns that are generally oriented in the transverse direction when the papermaking belt 10 of the present invention is mounted on a paper machine.

30 In papermaking, the term "machine direction" (MD) refers to a direction parallel to the passage of a paper web through the apparatus. The "cross direction" (CD) is perpendicular to the machine direction. These directions are indicated by the arrows in Figure 2 and a few subsequent figures.

Il. 97552 27 The definitions of warp and weft yarns used herein may sometimes differ from the definitions of said terms when describing the orientation of the yarns of a woven fabric when weaving a fabric in a weaving machine. In the field of weaving, the so-called -5 ko yarn as a warp or weft yarn depends in part on whether the fabric is an endless woven fabric that does not need to be looped to form an endless belt, or whether it is a planar woven fabric that must be seamed to form an endless belt. When the ky-10 has an endless woven fabric that does not need to be stitched into a loop, the yarns, called warp yarns in the weaving machine, run transversely in the paper machine. If, instead, the fabric is woven into a planar and then seamed into a loop, the yarns, called warp yarns in the 15 weaving machine, run in the machine direction on the paper machine.

As used herein, the terms "warp yarns" and "weft yarns" refer to the orientation of the yarns when the fabric is in place on a paper machine and not the orientation when weaving the fabric in a weaving machine. .

Figures 2-4 also show that in the woven reinforcing structure 33, some of the yarns intersect and form knees 105 in the fabric. As used herein, a "knee" is either a portion of a weft yarn passing over a warp yarn or a portion of a warp yarn passing over a weft yarn. surface (i.e., toward the. side of the paper 51 or the machine-facing side 52) 30 plane. Knuckles, which are the reinforcing 33 of the paper structure-facing side 51 (or "paper side knuckles") are designated 105 ^ knuckles which the reinforcing-facing 33 of the machine structure of the side 52 (or "backside knuckles") are 35 entries 1052. These the knees 105 may further be classified as either "warp generations" or "tissue generations" and use these designations.

As used herein, the term "warp knees" means knees formed by a portion of a warp yarn that passes over 5 weft yarns. A few such warp knees are used as 105a in the alternative embodiment of the papermaking belt 10 of the present invention shown in Figure 5 (which includes a single layer reinforcing structure 33). As shown by the cross-section 10 in Fig. 5B, the warp knees 105a may be either on the paper side 51 of the reinforcing structure 33 or on its machine side 52. The warp knees on the paper side 51 of the reinforcing structure 33 are designated 105ax, and per machine 15 The warp knees on the side 52 are denoted 105a2.

The knees formed by the portion of the weft yarn that passes over the warp yarn are referred to herein as "weft knees". A few such tissue knees are shown in Figures 20 and 2 as 105b. Figure 3 shows that the weft knees, as well as the warp knees, can either be on the paper side 51 of the reinforcing structure 33, such as the weft knee 105blr, or on the machine side 52 of the reinforcing structure 33, such as the weft knee 105 105b2.

Many types of woven elements are suitable for use as a reinforcing structure 33 in the papermaking belt 10 of the present invention. Suitable woven elements include porous monolayer woven elements 30 (having one array of strands in each direction and numerous openings therebetween), as shown in Figures 5, 5A and 5B. multilayer woven elements (woven fabrics having more than one group of strands in at least one direction), and 11 to 97552 29 fabrics having a few layers, each comprising interwoven strands.

Multilayer woven fabrics are preferred as reinforcing structures because they can extend the life of a composite-5 drip belt. As used herein, "composite papermaking belt" means a belt consisting of a lattice and a reinforcing structure. The papermaking belt 10 is subjected to considerable stress in the machine direction due to the fact that the belt 10 repeatedly passes over the papermaking machine in the machine direction, and also because heat is transferred to the belt from the imaging devices used in the papermaking process. Such heat and stress expose the papermaking belt to stretching. If the papermaking belt 10 stretches out of shape, its ability to fulfill its function of transporting paper through the papermaking process is impaired up to the point of unusability.

In order for the multilayer woven element to be suitable for use as a reinforcing structure in the papermaking belt of the present invention 20, it preferably has some type of structure that reinforces its machine direction yarns 53 to reduce the above-mentioned stretching problem. In other words, the multilayer fabric must have improved fabric stability in the machine direction. The arrangement of the warp yarns 25 53 should be such that any further reinforcement of the warp yarns does not reduce the projection of the open surface of the reinforcing structure.

As used herein, "surface projection" means the area formed by projecting the points delimiting the element 30 into a plane. More specifically, it is to be understood that these points are projected in a direction called the "direction z". The projection of the open surface of the reinforcing structure is indicated by A, in Figure 12 of the accompanying drawings. That is, the projection A <of the open surface of the reinforcing structure 33 is the surface seen when the reinforcing structure 5 is viewed in a direction perpendicular to either side of the reinforcing structure through the pores 39 forming straight lines of sight passing through the fabric.

Throughout this description, reference is made to the x, y, and z directions. As used herein, the directions x, y, and z are the directions of a rectangular coordinate system relative to the papermaking belt (or portions thereof) of the present invention. In the rectangular coordinate system described herein, the back face 12 of the belt is in a plane formed by the x- and y-axes, the x-axis is transverse, the y-axis is machine direction, and the z-axis is perpendicular to the plane defined by the x- and y-axes. As used herein, "z-direction" means directions parallel to the z-axis and perpendicular to the x- and y-axes. These directions are best seen in Figures 2-4.

The projection of the open surface of the reinforcing structure 33 should preferably be such that the reinforcing structure 33 is highly permeable (with respect to fluids such as air and water). The term "highly permeable" means that the air permeability of the reinforcing structure should be in the range of approximately 240 to 430 m3 / min per 1 m2 surface area with a pressure difference of 100 Pa. The air permeability of the reinforcing structure 33 is of great importance because it, together with the lattice, provides the air permeability of the composite belt. The air permeability 30 of the composite belt should be in the range of approximately 90 to 180 m3 / min. The preferred air permeability of the composite belt is about 150 m3 / min. In order for both the reinforcing structure 33 and the composite belt to be sufficiently permeable, it is preferable that the projection Aq of the open surface of the reinforcing structure is not less than

II

- 97552 31 about 30%, and most preferably the projection of the open surface is not less than about 40-50%.

As shown in Figures 2-4, one preferred reinforcing structure 33 is a multilayer woven element having a single layer yarn system with yarns running in the first direction and a multilayer yarn system having yarns running in the second direction, which direction is parallel to the normal of the first direction. In the preferred reinforcing structure shown in Figures 2-4, the first direction is the transverse direction. The simple layer of yarns running in the first direction comprises weft yarns 54. In the reinforcing structure shown in Figures 2-4, the multilayer yarn system is in the machine direction (i.e., the direction in which the fabric runs in the pape-15 breaker). The multilayer yarn system comprises a first warp layer C and a second warp layer D. Each of the warp layers C and D comprises a plurality of warp yarns 53. Although preferred fabrics for use as a reinforcing structure have a plurality of warp yarn layers running in a machine direction, the present invention may also be practiced using a fabric thread layers in the transverse direction. However, fabrics having multiple layers of warp yarn running in the machine direction are preferred because the additional threads travel in a direction that is generally subjected to the greatest stresses.

As shown in Fig. 3, the preferred multilayer reinforcing structure 33 has warp yarns 53 arranged vertically directly on top of each other. Vertically superimposed warp yarns 53 improve the stability of the composite belt 10 in the machine or process direction. Arranging the warp yarns on top of each other also results in a suitable open surface projection so that the belt 10 can be used in various types of papermaking processes, including papermaking processes in which blow drying is performed. The weft yarns are preferably arranged in such a way as to maintain and stabilize the vertical overlapping order of the warp yarns 53. The weft yarns 54 may also be placed vertically on top of each other, or they may be in some other relationship to each other. Numerous variations of such arrangements are possible.

Figures 6-11 show the tissue structure of the particularly preferred multilayer reinforcing structure 33 shown in Figures 2-4. As used herein, "tissue structure" means a technical model of tissue. The multilayer fabric is shown in Figures 6-11 without the surrounding lattice for clarity. Although the same fabric is shown in Figures 2-4 as a composite element in a papermaking belt (i.e., as a reinforcing structure for reinforcing the grid 32 of the papermaking belt 10 of the present invention), the fabric shown is also suitable for use as a papermaking belt without such a grid. However, the multilayer fabric described herein is preferably used in conjunction with some type of lattice.

As shown in Figs. 6-11, the first warp layer C of warp yarns 53 generally runs in the machine direction on the paper side 51 of the fabric. The individual warp yarns in the first warp layer C are repeatedly numbered 53a, 53b, 53c and 53d. The second layer D of warp yarns 53 runs in the machine direction on the machine side 52 of the fabric. Of the individual warp yarns in the second warp layer D, repetitive numbering 53e, 53f, 53g 30 and 53h extending over the fabric is used. As best seen in Figures 8-11, the individual yarns of the first warp layer C and the second warp layer D define pairs E, F, G and H of overlapping warp yarns. The individual yarns defining the pairs 35 E, F, G and H of overlapping warp yarns are arranged generally vertically • 97552 33 ti superimposed on each other. The numbering of the pairs E, F, G and H formed by these overlapping warp yarns also continues repeatedly over the fabric. Figures 8-11 show that the individual warp yarns 53a and 53e define a pair E of 5 overlapping warp yarns, the warp yarns 53b and 53f define a pair F of overlapping warp yarns, the warp yarns 53c and 53g define a pair F and the warp yarns 53d of overlapping warp yarns define a pair H of overlapping warp yarns 10. As shown in Figure 6 and Figures 8-11, the parallel pairs of overlapping warp yarns are spaced apart in a transverse direction to provide the desired open surface of the fabric.

As shown in Fig. 6, because the warp yarns 53 are superimposed, the effective density of the warp yarns 52 (i.e., the "yarn density" of the warp yarns) is doubled without decreasing the open surface of the reinforcing structure 33. As used herein, "yarn density" means a numerical value equal to the number of yarns per 20 width units of fabric (usually in inches) multiplied by the diameter of the yarn (usually also measured in inches). The "yarn density" may be further specified for fabric warp yarns (i.e., warp yarn density) or fabric weft yarns (i.e., weft yarn density).

A weft yarn such as weft yarn 54a in Fig. 8, 54b in Fig. 9, 54c in Fig. 10 and 54d in Fig. 11 is woven together with warp yarns 53a to 53h in the first and second warp layers. The weft yarns bind the individual warp yarns in the first and second warp yarn layers into pairs formed by overlapping yarns and prevent the warp yarns 53a to 53h from moving laterally and reducing the open surface of the fabric. These weft yarns 54a, 54b, 54c and 54d are also repeatedly numbered over the fabric. The weft yarns 54 are woven together with 35 pairs of overlapping warp yarns - 97552 34 to form a special weave structure (or more specifically a "warp balancing weft structure"). The weft yarns 54 hold the warp yarns on top of each other and generally vertically aligned.

The special fabric pattern formed by the warp yarns 53 and the weft yarns 54 in the fabric shown in Figures 6-11 is known as a four-viral repeating structure. As used herein, "strand" means the number of unique structures that either the warp yarn or weft yarn 10 forms with the yarns to be woven with it before repetition occurs (i.e., a four-strand structure would be a structure that is repeated after each group of four yarns).

The particular structure in which the warp yarns 53 are woven is best seen in Figures 6 and 7. As shown in Figures 6 and 7, the first warp yarns of the first warp layer C (such as the warp yarn 53b shown in Figure 7) repeatedly pass over three woven yarns and one woven yarn. under the weft yarn in the tissue structure.

20 As used herein, the term "apply to a fabric" means to place a weft yarn between separated warp yarns. The second warp yarns of the second warp layer D (such as the warp yarn 53f shown in Fig. 7) repeatedly pass over one weft yarn introduced into the fabric and under the three weft yarns 25 woven into the fabric in the fabric structure.

The particular structure in which the weft yarns 54 are woven is best seen in Figures 6 and 8-11. As shown in Figures 8-11, the warp yarns 53 are held vertically on top of each other by a simple network of weft yarns 54 woven between overlapping warp yarns. The weft yarns 54 are woven around the overlapping warps following a repetitive pattern in which the weft yarn (such as the weft yarn 54a in Figure 8) first passes over a first pair of overlapping warp yarns 35, between a second warp yarn of a pair of overlapping 97552 35 warp yarns. between the warp yarns of the pair G ali and the fourth pair of overlapping warp yarns H. That is, each weft yarn 5 54 passes over and under every other pair of overlapping warp yarns and between these pairs of overlapping warp yarns formed by each other pair of overlapping warp yarns.

As shown in Figs. 6 and 8 to 11, adjacent weft yarns are woven around the warp yarns 53 in the same manner. However, as shown in Fig. 9, adjacent weft yarns, such as weft yarn 54b, move by one pair of warp yarns relative to the position of the first weft yarn. Thus, the 15 adjacent or second weft yarns pass between the warp yarns of the first pair of overlapping warp yarns, over the second pair of overlapping warp yarns, between the warp yarns of the third pair of overlapping warp yarns, and between the warp yarns of the fourth pair of overlapping warp yarns. As shown in Figs. 10 and 11, the third warp yarn 54c similarly moves one pair of warp yarns relative to the second weft yarn, and the fourth warp yarn 54d moves one pair of warp yarns relative to the third weft yarn 25, respectively. This pattern is repeated every fourth weft yarn-sat. As shown in Fig. 6, this provides a woven structure in which the intersections 55 formed by the weft fabrics 54 pass stepwise in the weft direction across the warp yarns.

One variation of the above fabric structure can be obtained by interchanging the weft yarn 54c shown in Fig. 10 and the weft yarn 54d shown in Fig. 11. This results in a truncated stepped pattern of weft intersections 55 in the weft direction. In this truncated Fig. 35, the two first intersections 55 are diagonal. However, the third intersection point 55 moves over the third warp yarn to the fourth warp yarn, and the fourth intersection point 55 moves over the third warp yarn to the fourth warp yarn, and then the intersection point 55 5 moves back diagonally to the third warp yarn. This weave structure also keeps the warp yarns in the pairs formed by the overlapping warp yarns suitably arranged. However, in this weave structure variation, the two warp yarns pass together between two weft yarns inserted into the rin-10 lattice fabric. The fabric structure first described does not have two weft yarns inserted into the fabric, between which the warp yarns pass simultaneously, which gives the fabric structure a slightly better balance.

Various combinations of yarn materials, cross-sectional dimensions, and cross-sectional shapes can be used in this preferred fabric. The material of the yarns, the dimensions of the cross-section and the shape of the cross-section are determined by the respective use of the fabric.

20 Although the structural materials of warp yarns and weft yarns may vary, the yarn material should be such that the yarns have the ability to reinforce the resin lattice and withstand stresses as well as repeated heating and cooling without undue stretching. Suitable materials from which yarns can be formed include polyester, polyamide, highly heat resistant materials such as KEVLAR and N0MEX grades, and any other materials known to be used in papermaking fabrics. However, the preferred yarn material is polyester. The construction material of the yarns in the different layers and yarn systems may vary, with the yarns of one layer or yarn system being formed of one material and the yarns of the other layers or yarn systems of a different material. However, all the yarns of the different layers and yarn systems are preferably made of substantially the same material.

Any suitable yarn cross-sectional dimensions (or sizes) may be used, as long as the air and water flow through the channels 36 is not significantly impaired during paper web processing and the integrity of the papermaking belt 10 as a whole is maintained. Yarns with the same cross-sectional dimensions can be used in all layers or yarn systems, or the size of the yarns can be different in different layers and yarn systems. For example, if yarns with a circular cross-section are used, the yarns of the warp systems C and D may have one diameter and the yarns of the weft system may be larger in diameter or smaller in diameter. If larger diameter weft yarns are used, the weft yarns are stiffer and cause more curl warp yarns. Other variations include those in which the yarns of the warp system C and the weft system 54 are similar and the yarns of the warp system D are different. 20 Similarly, the yarns of the warp system D and the yarns of the weft system may be similar and the yarns of the warp system C may be different. Alternatively, the yarns may be different in warp system C, warp system D, and weft system each. In the case of yarns of circular cross-section, the preferred diameter range of the yarns is about 0.10 to 0.30 mm. The most preferred diameters are about 0.22 mm for the warp yarns 53 and about 0.28 mm for the weft yarns 54. Depending on the application, larger diameter yarns can also be used.

Yarns having any suitable cross-sectional shape may be used as long as the yarns do not interfere with the flow of fluids through the channels 36 during web processing and the integrity of the papermaking belt 10 as a whole is maintained. Suitable 35 cross-sections include circular, oval, square and 97552 38 rectangular cross-sections. The cross-sectional shapes of the yarns in the different layers and yarn systems may also vary between the layers and the yarn systems. However, both the warp yarns 53 and the weft yarns 54 5 preferably have a circular cross-section.

Irrespective of whether the reinforcing structure 33 is the multilayer woven structure described above, only some other structure, such as gauze or perforated sheet, the first portion P01 of the reinforcing component 10 40 forming the reinforcing structure 33 further has a first guide 0X and the second portion of the reinforcing structure 40 PO 2 is the second opacity O 2. The two opacity O 1 and O 2 are in such a ratio that the second opacity O 2 is lower than the first opacity (i.e., the second part is relatively less opaque).

The first opacity Ox should be sufficient to substantially prevent curing of the photosensitive resin material forming the lattice 32 when this photosensitive resin material is in its uncured state and the first portion P01 is placed between the photosensitive resin material and the actinic light source. It should be understood that only a portion of this photosensitive resin material is located on the opposite side of portion P01 to the light source. The rest of the resin material is elsewhere. The purpose of the first-25 portion (i.e., the "opaque portion") P01 is to prevent the portion of the resin material on the other side of the first portion P01 from curing during the manufacture of the papermaking belt 10 of the present invention. This uncured resin can be removed to leave passageways 30 37, that provide surface texture irregularities 38 in the belt 10 backside 12 of the counterpart-purity network 35a.

The characteristics and dimensions of the first part PQ1 should be such that the pathways 37 and surface texture irregularities 38 caused by the removal of the uncured resin - 97552 39 provide the desired amount of backing texture to the finished belt (as described below). PQ1 of the first part should generally be located in the machine-facing side of the reinforcing structure 52 WF 5 or vicinity of it. Such a location ensures that the resin to be cured is generally on one surface 35 of the belt grid 32 instead of the inside of the grid 32. As used herein, an "inner portion" is that portion of the grid 32 that is between the first and second surfaces 34 and 35. If the first portion Poi is positioned in this way, too much resin between the first and second surfaces 34 and 35 of the lattice 32 will not cure. This generally weakens the lattice 32 and also the bond between the lattice 32 and the reinforcing structure 33.

The first part 15 P01 may be any part of the reinforcing component 40 provided that it prevents sufficient curing of the resin 38 to form the desired passageways 37 and surface texture irregularities in the backside network 35a. Thus, the first part P01 may comprise a part or parts of one or more structural components 40a. When the reinforcing structure 33 comprises a woven element, the first portion P01 may be, for example, one or more portions of a single yarn, one or more portions of a plurality of yarns, an entire yarn, a plurality of complete yarns 25, or any combination thereof.

In one preferred embodiment of the present invention, the first part P01 comprises a whole warp yarn or yarns. It is generally preferred that the warp yarns 53 form a first portion instead of the Pox weft yarns 54. This advantage is due to the fact that in the preferred reinforcing structures, the woven structure of the warp yarns 53 causes them to be generally closer to the part which becomes the second surface 35 of the truss 32 than the weft yarns. The reinforcing structure 33 most preferably comprises the preferred multilayer woven element described above having vertically overlapping warp yarns, and the first portion P01 comprises at least some of the warp yarns in the second weft layer D. This preferred arrangement is shown in Figures 3 and 4. Since the first portion P01 is described as comprising at least some of the warp yarns 53 in the second warp layer D, the first portion P01 may comprise, for example, every other warp yarn (as shown in Figure 11B) or each warp yarn (as shown in Figures 3). , 4 and 11A), a third warp yarn, etc., or a pair of each of the two overlapping warp yarns, etc. There are an unlimited number of possible combinations, all of which are within the scope of the invention.

Furthermore, as shown in Fig. 11C, in one alternative embodiment of the present invention, the first portion P01 comprises an opaque coating C0 applied to at least a portion of either side of the reinforcing structure 33. For the reasons set out in the opaque coating is preferably applied to the reinforcing construction 20 I per three machine-facing side 52. The opaque coating C 0 can be applied in any manner or to any 33 toward the reinforcing pattern structure facing side 52, provided in the backside network 35a form the desired passageways 37 and pintateks -25 irregularities 38. Thus, the opaque coating C0 can be applied randomly, uniformly, regularly, or according to a certain pattern. The opaque coating C0 can be applied to the reinforcing structure by any means known in the field of coating articles.

The first portion P01 is generally given a first opacity Oh before the reinforcing structure 33 is incorporated into the papermaking belt 10. A single yarn can be given a first opacity 0! by mixing a suitable opaque material during the manufacture of the yarns with a polyester material forming the yarns. Alternatively, the individual yarns (or parts thereof) may be given a first opacity P01 by coating the individual yarns with an opaque material 5 before weaving them into a fabric. Suitable opaque materials include substances that either absorb, scatter, or reflect actinic light. Examples of actinic light absorbing materials include organic dyes and carbon black. One example of an actinic light scattering material is TiO 2. Actinic light reflecting materials may include one or more metals doped or incorporated into the fabric. The same materials are also suitable for use in the opaque coating described above. The opaque material used is preferably opaque to light having a wavelength of approximately 200 to 400 nm.

The reinforcing structure 33 of the present invention defines a few surface projections that are useful in describing the irregularity of the surface texture of the passageways 37. homogeneities 38 and position 32 of the second surface 35 of the framework 5 in the backside network 35a. As shown in Figures 12-18, the reinforcing structure 33 defines at least the following surface projections: projections of the pore surfaces; a previously defined open surface projection (which is the sum of the projections of all the pore surfaces of the reinforcing structure); ra-10 kennel component surface projections; the projection of the reinforcing surface (which is the sum of the projections of all the structural component surfaces of the reinforcing structure); warp surface projections (and total warp surface projection); weft surface projections (and total weft surface projection); Polve-15 kepintojen projections, including the machine-side Polve kepintojen projections, and the first and second surface projections. In addition, when there are several warp or weft layers or the like, there may also be projections of the warp yarn surfaces of the first - 97552 42 warp layer and the second warp layer, etc.

The projections of the pore surfaces are indicated in Figure 12 by the notation Ap *. As used herein, "pore surface projections" means individual surface projections defined by the projections of the pores 39 of the reinforcing structure 33. That is, when viewed from the reinforcing structure 33 from a direction perpendicular to either side of the reinforcing structure, each pore 39 forms 10 straight lines of sight passing through the reinforcing structure, which form projections of the pore surfaces Apt.

The projection AgC of the structural component surface is shown in Fig. 13. As used herein, "projection of the structural component surface" means the surface determined by the projection of the individual structural component 40a of the reinforcing structure 15 33. As used herein, "projections of structural component surfaces" means a surface defined by the projection of more than one, but not all, structural component 40a of the reinforcing structure 33.

A portion of the projection A „of the reinforcing surface is shown in Fig. 13. As used herein, the term" projection of the reinforcing surface "means a surface defined by the projection of the reinforcing component 40. As shown in Figs. 12 and 13, the projection A „of the reinforcing surface is substantially the opposite of the projection Aq of the open surface of the reinforcing component; it is the part of the reinforcing structure 33 that breaks the line of sight. The projection A „of the reinforcing surface is complementary to the projection Aq of the open surface, because together they form the projection of the entire surface of the reinforcing structure 33.

30 Figures 14 and 15 show the projection of the warp surfaces. As used herein, "warp surface projection" A ^ refers to the surface defined by the projection of the individual warp yarns 53 of the reinforcing structure 33. In Figure 15, the warp surface projections A ^ are shown as diagonal shaded areas 35 between dashed lines. Dashed lines could also extend the paper of the reinforcing structure. per side 51 above. in general, however, this invention is concerned with passageways and surface texture irregularities which are the reinforcing 33 of the paper structure per 5 above the plane of side 51 of the. When the position of a passageway or surface texture irregularity is described herein with reference to a projected area, the passageway or irregularity is because the reinforcing 33 per paper structure 10 between the plane of the side 51 and the backside 10 of the belt determined. When it is said that a passageway or surface texture irregularity is warp areas shown in Figures 14 and 15, the projections "inside" can be any point within the areas shaded in Figure 14 or shaded in slashes in Figure 15. In addition to the warp surface projection defined by each individual warp, there is a "total warp surface projection" A 1 comprising the sum of the projections of the individual warp surfaces. in the fabric area.

Figures 16 and 17 show projections of tissue surfaces 20 Å. As used herein, "weft surface projection" Awt means a surface defined by the projection of individual weft yarns 53 of the reinforcing structure 33. In addition to the hexagonal surface projection Awt, there is a "total weft surface projection" Α „ϊ0 (part of which is shown in Figures 16 and 17), which comprises the sum of the projections A„ t of the individual weft surfaces over the entire reinforcing structure.

As used herein, "knee surface projection" of a reinforcing structure 33 means a surface defined by the projection of one knee 105 of a woven reinforcing structure. As shown in Figs. 18A to 18C, the knee surface projection AK is that portion of the reinforcing structure 33 in which the warp yarn and the weft yarn overlap and which cut off the line of sight passing through the reinforcing structure 33. In addition, the projections of the knee surfaces can be classified as projections AKHp (projection surface formed by a warp yarn passing over the weft yarn) or projections AKwt (projection surface formed by a weft yarn passing over the warp yarn) 35. Loimipolvekepintojen projections AKwp and weft projections AKwt can be further luoki-5 telia paper side (that is, paper-facing side) of loimipolvekepintojen as projected AKwpl or weft as projected AKwtl and the machine-facing side (or machine side) loimipolvekepintojen a projected ^ j or as projected weft A 'WT2 (the according to which 10 sides of the fabric the knees are formed).

Part of the first surface projection Ax and part of the second surface projection A2 are shown as shaded areas in Figs. 11A and 11B, respectively. As used herein, the term "first surface projection" Ax is a surface defined by a Poi projection of a first portion of the reinforcing structure 33 having a first opacity 02. The remainder of the reinforcing structure 33 generally has a second opacity 02 and defines a second surface projection A2. Figures 11A and 11B show that the purity of the framework 32 to 20 counterpart network 35a of the passageways 37 are positioned predominantly in the first projected area Ax area (first portion is formed PQ1 then each warp yarn 53, the second warp yarn 53 or any other part of the reinforcing structure).

The second main element of the papermaking belt 10 of the present invention is a grid 32. Figures 2-4 show general characteristics of the grid 32. In a preferred embodiment of the present invention, the lattice 32 is formed by treating a generally liquid mass of material 30 such that the material in solid form at least partially surrounds the reinforcing structure 33 such that the reinforcing structure 33 is positioned between the first surface 34 and at least a portion of the lattice 32. from the second surface 35. In addition, the material 35 must be treated so that the lattice 32 has a plurality of channels 36 passing between the first surface 34 and the second surface 35 of the lattice 32. The material must be handled in such a manner that the first surface is formed by the paper side network 34a which surrounds and 5 define a grid 32 in the first surface 34 of the channels 36 holes. Further, the material must be manipulated so that the second surface 32 of the grid 35 is the backside network 35a of the channels 36 of contrasting passageways 37 that provide surface texture irregular probabilities 38 and 10 in the backside network 35a.

The mass of material treated to form the grid 32 may be any suitable material, including thermoplastic and photosensitive resins, but the preferred material for use in forming the grid 32 of this invention is a liquid photosensitive polymeric resin. The selected material can likewise be treated in a variety of ways to form the desired lattice 32, including mechanical stamping or drilling, curing the materials by treating them with different temperatures or energy sources, or using a laser to cut channels in the material. The method of processing the material forming the grid 32 will, of course, depend on the selected material and the properties of the grid 32 to be formed from the mass of material. The preferred method for treating the photosensitive resin is to control the exposure of the liquid photosensitive resin to light having an activating wavelength.

(With paper described above, ie. Kosketukses-30 At the side 11 and the backside 12) of the papermaking belt of the present invention, 10 sides and the framework 32. The relationship between the surfaces is best seen in Figures 32 a first surface 3 and 4. The grid 34 is preferably formed of paper with the papermaking belt 10 in contact with the side 11. this ratio is normally prevails in most-35 in embodiments of the present invention, since the reinforcing structure 97 552 46 3 34 is positioned between and at least a portion of the first surface 32 of the framework 32 to the second surface of the grid 35. in other words, the first surface 32 of the truss 34 generally covers the reinforcing structure 33 the paper 5 per side 51.

However, the second surface 35 of the grid 32 of the papermaking belt 10 of the present invention does not necessarily always form the back side 12 of the papermaking belt 10. Because

K

the reinforcing structure 33 is positioned between the first surface 34 of the lattice 32 and at least a portion of the second surface 35, the second surface of the lattice 32 may either completely cover the reinforcing structure 33 (although this is not generally the case when the papermaking belt is made by the method described herein); cover only a part of the reinforcing structure 15 33, or not to cover any parts of the reinforcing structure and to be completely in the pores 39 of the reinforcing structure 33.

In the former case, the second surface 35 of the grid 32 and the back side 12 of the papermaking belt 10 are the same thing. In the second case, the back-side 12 of the papermaking belt 10 consists in part of the second surface 35 of the lattice and in part of the exposed portion of the reinforcing structure. In the third case, the back side 12 of the papermaking belt 10 also consists partly of the second surface 35 of the grid 32 and partly of the reinforcing structure 33, but the machine side 52 of the reinforcing structure 33 is completely exposed on the back side 12 of the papermaking belt 10.

Figure 2 shows that the first surface 34 of the grid 32 (and the paper-contacting side 11 of the papermaking belt 10) consists of a portion of the network designated 32a. As used herein, the term "network" refers to portions of the grid 32 that surround the channels 36 and define a network-like pattern. In other words, the network 32a is an integral part of the grid 32. As shown in the enlarged photographs of the papermaking belt 10 of the present invention, 97552 47, Figs. 36A and 36B, the grid 32a has two mesh surfaces 34a and 35a. As used herein, "network surface" means one of the surfaces of the network 32a surrounding the channels 36. These network surfaces are also referred to herein as the "knees" of the ris-5 stick 32. However, the knees of the lattice 32 should be distinguished from the previously described knees formed by the wires of the reinforcing structure 33. The term "network surface" will also be used to Trokhan and Johnson patents, which are incorporated herein by reference. As used herein, the term 10 "network surface" will be modified by specifying whether the network surface "paper side network surface" or the "backside network surface".

The term "paper side network surface", (or "paper side network") refers to the upper lattice 32 or 15 in the first surface 34 of the fixed part of the grid.

Thus, the surface of the grid, referred to as the "network" herein incorporated by reference in those patents generally corresponds to the paper side network surface in the present specification. The paper side network surface is represented by reference numeral 34a-20 silicon drawings.

The term "backside network surface", (or "backside network") refers to the framework 32 to the bottom end-nalla a second surface 35 on the fixed part 32 of the grid. The backside network surface 35a is denoted 25 in the drawings.

As 2-4 shown in the figures, 32 of first surface 34 comprises both the paper side network surface 34a and the first conduit openings 42. The first conduit openings 42 in the channels 36 of openings of the framework 32 ensimmäisel-30 DO surface 34. The grid 32 second surface 35 comprises both the backside network surface 35a and second conduit openings 43. the second conduit openings 43 in the channels 36 of openings of the framework 32 on the second surface 35 of the framework 32 of the paper side network surface 34a and the first surface 34 of Ensim-35-like channel-air openings 42 are described herein often "complementary 97 552 48 tare "because together they form one complete surface of the lattice, respectively. For the same reason, the backside network surface 35a and second conduit openings 43 are described herein as complementary.

5 As shown in Figure 2, the paper side network 34a is macroscopically monoplanar, patterned, and continuous. This allows a uniform pattern to be formed in the paper web during processing. By "macroscopically monoplanar," it is meant that when a part of the paper with a 10-Preparation of the belt 10 in the paper side 11 disposed in a plane, the paper side network 34a is essentially in one plane. It is said to be "substantially" single-level in order to understand the fact that deviations from absolute flatness are tolerable, but not preferred, as long as the deviations are not so substantial as to adversely affect the performance of the product formed by the papermaking belt 10. The paper side network 34a is said to be "continuous" because the lines formed by the network on the paper side network surface 34a must form at least 20 one essentially unbroken net-like. pattern. The pattern is said to be "substantially" continuous to understand that pattern breaks are tolerable, but not preferred, as long as the breaks are not so substantial as to adversely affect the performance of the product formed on the papermaking belt 10.

Channels (i.e., "guide channels") 36 extending from the first surface 34 of the grid 32 to the second surface 35 of the grid 32 are shown in Figures 2-4. Each channel 36 defines certain features, including a channel portion, i.e., a roll of 30, commonly referred to as 41; a mouth or channel opening (also known as "large pores"), such as a first channel opening 42 formed on the first surface 34 of the lattice 32; a mouth or channel opening, such as a second channel opening 43 generally formed on the second surface 35 35 of the grid 32, and channel walls, generally denoted by 44, defining the dimensions of the channels 36 in the interior of the grid 32. (The "inner portion" of the lattice is the portion of the lattice 32 between the first and second surfaces 34 and 35.) As shown in Figures 2-4, the walls 44 of the channels 36 form the inner walls 44a of the lattice 32. The inner walls 44a of the grid 32 are surfaces of the grid 32 that coincide with the walls 44 of the channels 36. That is, the walls 44 of the channels 36 have the same, i.e., congruent, boundaries with the inner walls 44a of the lattice 32. The second channel openings 43 are described as being formed "generally" on the second surface 35 of the grid 32, because if one or more passageways 37 intersect the second channel opening 43, at least a portion of the second channel opening 43 may move in a manner that is actually the grid 32. the first 15 between its surface 34 and the surrounding portions of the second surface 35 of the lattice 32. That is, portions of the second channel openings 43 may be inward (toward the center of the belt) from a plane defined by portions adjacent the second surface 35 of the truss 32.

Figure 2 shows that the first channel openings 42 in the first surface 34 of the grid 2 are uniform and of a certain shape. The 32 second surface 35 of the framework second conduit openings 43 are also pohjimil, the same geometry as the first conduit openings 42. Ku and 25 of Figure 34B shows the framework 32 in the backside network 35a appear in the passageways and surface texture irregularities can cause the second conduit openings distorted and very irregular in shape. This distortion is not particularly problematic in the context of the present invention 30, because the backside network 35a which surrounds the second conduit openings 43 does not contact with the paper web during formation and press the pattern.

Although there is an unlimited variety of possible shapes for the openings 42 and 43 of the channels 36 35, certain loose instructions may be given for selecting the particular shape of the channel opening. These instructions are set forth in U.S. Patent 4,528,239 ("Deflection Member", Paul J. Trokham, July 9, 1985), column 5, line 34, column 10, line 35, 5, which is incorporated herein by reference.

The shape and order of the channels shown in Figure 2 are together in a particularly preferred form. The shape of the channel openings 42 and 43 shown in these figures is referred to herein as the "linear Idaho pattern." As shown in Fig. 10 and 2, the channels in the shape of a linear Idaho pattern are roughly in the shape of modified transformers. The shape of the channels 36 is said to resemble a modified parabola, since in this top view each channel 36 has four sides, the sides on opposite sides being parallel, the angle between the parallel sides not being a right angle and the corners between the parallel sides being rounded. Thus, channel openings in the form of a linear Idaho pattern can also be described as circular-angular.

The structural details of these linear Idaho patterned channels 36 are shown in Figure 19. Figure 19 shows only a portion of the grid 32 of the papermaking belt 10 showing the repetitive pattern 25 formed by the channels 36. In addition, for clarity, only the paper side network surface 34a is shown for all but one channel. This particular shape of the channels 36 is achieved as described below. However, as will be apparent, it is possible to change the order of the steps 30 and achieve the same result. It is also apparent that the dots, lines and circles used to provide the shape of the channels are not actually visible in the channels 36 formed by the procedure described below (except where they form the walls 44 of the channels 36).

97552 51

To obtain a geometric shape according to the linear Idaho pattern, two points P3 and P2 are initially selected, which are at a certain distance dx from each other. The line connecting these two points P3 and P2 is called the axis of the channel 5 in the machine direction, i.e. the longitudinal axis AL. The distance between these two points Px and P2 (which is equal to the length of the longitudinal axis AL) is preselected. At each of these points, a circle is drawn with a certain radius R2. Next, a line A 1 is drawn, which is perpendicular to the longitudinal axis AL of the hub ka-10. This next line A, is drawn across the longitudinal axis AL so that it bisects the longitudinal axis AL. Then two points P3 and P4 are placed on the second line Aj equidistant from the longitudinal axis A1. Also the distance between points P3 and P4 va-15 Iita in advance. The line A 1 connecting the points P3 and P4 is called the channel axis in the transverse direction, i.e. the transverse axis. A circle with a certain radius R2 is drawn at each of the points P3 and P4. Although the latter radius R2 need not be equal to the radius Rx of the previously drawn circle, in the preferred figure shown in Fig. 19, R 1 is equal to R 2. As a final step, the tangents L1f L2, L3 and L4 are drawn between the parts of the previously drawn circles. The tangents are drawn in such a way that they are tangential to those parts of the circles which are farthest from the point of intersection of the longitudinal axis AL and the transverse axis Aj. A line running around the perimeter of the pattern thus described forms the walls 44 of a linear Idaho patterned channel 36. As shown in Figure 19, the sides 30 of the first channel openings are marked 30a, 45b, 45c and 45d and the rounded corners 46 adjacent sides are marked 46. Markings 45e, 45f, 45g and 45h are used on the respective sides of the second channel openings 43. The corresponding corners of the second channel openings 43 are used to denote 46a.

97 £ 52 52

Other suitable shapes of the channels in the grid 32 of the papermaking belt 10 of the present invention include, but are not limited to, the modified hexagon described in the Trokham and Johnson 5 patents, incorporated herein by reference, and the "knot or blue curve pattern" shown in Figure 20.

Regardless of the shape of the channel openings, whether in the preferred Idaho linear pattern or in some other form, the number of channels 36 per defined belt area 10 and the relative space occupied by the channel openings in the grid 32 of the papermaking belt 10 should be within specified limits.

The number of channels 36 in the grid 32 is generally expressed as the number of channels per square inch of the total area of the grid 32. As used herein, the term "lattice of the total surface area" refers to either the amount of the paper side network surface 34a of the surface area and the first conduit openings 42 occupied by the complementary surface area or the backside network surface 35a of the surface area and the amount of other networks 43 occupied by the complementary auk-20 surface area. The number of channels 36 in the grid 32 should preferably be about 10 to 1000 per square inch.

The relative amount of space occupied by the channel openings is usually expressed here as a percentage of the size-25 female area of the grid 32. It is also common in this specification to express the relative space occupied by the complementary network surfaces 34a and 35a of the lattice as a percentage of the total area of the lattice 32. The paper side network surface 34a and the backside network surface 35 occupied by 30 space is referred to herein generally as "knuckle areas" of the framework 32 corresponding to the surfaces. These knuckle areas are shown in Figures 19A and 19B markings N and, respectively, An2. The paper side knuckle area (or first surface knuckle area) AN1 (shaded Figure 19A) is the paper side of the ver-35 Revenge of the surface 35a of the projection plane in the z-direction. track surface 97 552 53 knuckle area (or second surface knuckle area) A "2 (shaded in Figure 19B) is a backside network surface projection plane in the z-direction. The channel openings in the proportionate amount of space 35A can be derived from the space occupied by the knee areas 5 of the lattice 32. Since the area occupied by the channel openings and the area occupied by the corresponding network surfaces are complementary, the sum of these two percentages is 100% If either the knee areas or the relative space occupied by the channel openings are known, complement-10 rine area to decrease known percentage of 100%.

The relative space occupied by the first channel openings 42 in the first surface 34 of the grid 32 is preferably about 30 to 80% of the total area 15 of the grid 32. That is, the first surface 34 of the lattice 32 contains about 20 to 70% of the knee area. The relative space occupied by the second channel openings 43 in the second surface 35 of the grid 32 is preferably about 30 to 80% of the total area of the grid 32. That is, the second surface 35 of the lattice 32 20 contains about 20 to 70% of the knee area.

The specific arrangement between the individual channels 36 and the channels 36 shown in Figure 2 is only one possible way of arranging the channels 36. There are a number of preferred arrangements between the individual channels 36 and the channels 36. Some of these preferred placements and spacing are set forth in U.S. Patent 4,528,239 ("Deflection Member", Paul D. Trokhan, July 9, 1985), column 8, lines 35-58, which is incorporated herein by reference. However, one particularly preferred arrangement between the channels 36 and the channels 36 30 is the two-sided stepped opening formation shown in Figure 2. It can be seen from Figure 2 that in this particularly preferred arrangement and spacing of the openings, the openings 42 of the channels 36, such as the first channel openings 42, have a size 54 to 97552 and a mutual distance such that the edges of the channels 36 extend past each other in any direction.

In one particularly preferred embodiment of the papermaking belt 10 of the present invention having 5 linear Idaho patterned openings, the parameters of the channels 36 (i.e., the number, size, and placement of the channel openings) are referred to herein as the "linear Idaho model 300 with 35 % knee surface ". The first digit of the above expression represents the number of channels 36 per square inch in the grid 32. Thus, the grid 32 has 300 channels per square inch. The second number (ie. 35% knuckle area) refers to the paper-side network surface 34a to the approximate surface area, or knuckle area. In this preferred embodiment, the structure 15 of the papermaking belt is such that the backside network surface 35a of the surface area, or knuckle area is about 65%.

The dimensions used to form the channels 36 as well as the total dimensions of the channels and the distance between the channels 36 in the preferred linear Idaho model 300 with 35% knee surface are shown in Figure 19. In the linear Idaho model 300 with 35% knee surface, the following lengths are used to form the channels. radii: dt is 1.0795 mm (0.0425 inches), d2 is 0.62785 mm (0.024712 inches), and Rx and R2 are both 0.3050 mm (0.012008 inches). The overall dimensions of the channel openings and the distance between the channels in the first surface 34 of the grid 32 are shown by a series of letters in Figure 19. In Figure 19 the letter "a" represents the length in the machine direction ("MD"), i.e. simply the "length" of the opening, "b" ("CD"), i.e., the "width" of the opening, "c" the distance between two parallel openings in the machine and transverse directions, "d" the distance between the parallel openings in the transverse direction, and "e" the distance between the parallel openings in the machine direction. In this preferred embodiment, "a" is 1.6892 mm li - 97552 55 (0.066506 inches), b 1.2379 mm (0.048737 inches), c 0.28153 mm (0.011084 inches), d 0.92055 mm (0.036242 inches) and e 0.30500 mm (0.012008 inches).

The channels 36 have a channel portion between the channel openings 5 42 and 45. These channel portions 41 are bounded by the walls 44 of the channels 36. The general characteristic features of these channel portions 41 and the walls 44 are shown in Figures 2-4. Figures 2-4 show that the cavities formed by the channels 41, i.e. the channels 41, extend through the entire papermaking belt 10 10 in the thickness direction. As shown in Figure 2, the channels 36 are generally separate. By "separate" is meant that the channels 36 form separate channels separated by a grid 32. The separation of the channels 36 is particularly apparent from the top 15 view of Figure 2. Channel 36 is described as being "However, generally speaking, the" separate, since, as shown for example in Figure 7B, the channels 36 may not completely separate the framework 32 on the second surface 35 when the backside network 35a is the passageways 37. The conduits 36, 20 are also shown to be isolated in keep in mind that. the channels 36 have no connection to each other within the body of the papermaking belt 10. This isolation of the channels 36 from each other is particularly evident from the cross-sectional views of Figures 3 and 4. Thus, the substance (for example, the running of 25 materials, as removed from the paper water) the transition from one channel to another is generally not possible unless the transfer is effected outside of the papermaking belt 10 of the frame or if not, such as for example in Figure 37B The belt, the transfer is effected in the passageways 37 Pape-30 rinvalmistushihnan 10 on the backside 12 under certain in sections.

Figures 3 and 4 show the orientation of the channels 36 in the grid 32. As shown in Figures 3-4, the channels 36 have a vertical axis denoted Ay. The vertical axis Ay is an imaginary line passing through the center of each channel 35 36 between the first channel opening 42 and the second - 97552 56 channel opening 43. The orientation of the vertical axis Ay determines the orientation of the channels 36 in the grid 32 relative to the surfaces 34 and 35 of the grid 32. Thus, it should be understood that in the context of the present invention, the vertical axis Ay is not always in a fully vertical position; it is only relatively vertical to the longitudinal and transverse axes A1 and A1 of the channels 36. The orientation of the vertical axis Ay of the channels 36 can vary widely from a position in which the vertical axis Ay is generally perpendicular to the first and second surfaces 34 and 35 of the grid 32 10 to a position where the vertical axis is oriented so that the channels 36 are formed at some angle to the grid 32. however, the vertical axis Ay is preferably generally approximately perpendicular to the first and second surfaces 34 and 35 of the grid 32, as shown in Figures 3 and 4.

The cross-sectional profile of the walls 44 of the channels 36 is shown enlarged in Figure 21. The profile of the walls 44 of the channels 36 may be relatively straight, curved, partially curved, and partially straight or irregular when viewed in cross-section. It should be noted that in drawings other than Fig. 21 showing the walls 44 of the channels 36, the walls 44 of the channels 36 are shown schematically as straight lines to facilitate illumination. However, as shown in Fig. 25 21, it is assumed that the profile of the walls 44 of the channels 36 may be non-linear from the upper surface 34 of the grid 34 to the lower surface 35 of the grid 32.

As shown in Figure 21, the profile of the walls 44 of the channels 36 is a substantially straight line (in the area 30 represented by the number 47) from the first surface 34 of the truss 32 to the area of the walls 44 beginning approximately at the points indicated by the number 48. The points denoted by 48 are approximate points where the paper-facing side 51 of the reinforcing structure 33 meets. 35 At the points 48 where the paper-facing side 51 of the reinforcing structure 33 to 97552 57 meet, the profile 44 of the walls 44 of the channels 36 is more vague. At this point, the profile of the walls 44 of the channels 36 generally becomes somewhat irregular. The portion of the walls 44 of the channels 36 having an irregular profile is denoted by 49 in Figure 21. The irregular portion of the profile of the walls 44 of the channels 36 is formed by curing the liquid photosensitive resin to a grid 32. The ultraviolet light used to cure the resin is supplied by light sources. the paper-facing side 51 and the paper with the above on the side 51 of the liquid photosensitive resin to be. The light rays diffuse or scatter to a certain extent when they encounter the strands of the reinforcing structure 33, which causes the light-sensitive resin to cure irregularly. Thus, the exact starting point of the irregular portion of the walls 44 will vary depending on where the reinforcing structure 33 meets.

The relationship of the walls 44 of the channels 36 to each other (i.e., the slope of the walls) may vary from cases where the walls 44 are parallel to cases where the walls 44 are tilted either outward or inward from the upper surface 34 of the grid 32 toward the lower surface 35 of the grid 32. Since the walls 44 of the channels 36 form the inner walls-25 of the lattice 32, as shown in Figures 2-4, the inner walls 44a of the lattice 32 may also be inclined. As used in connection with the inclination of the walls 44 of the channels 36 or the inner walls 44a of the lattice 32, the term "outward" means a relationship in which the distance between opposite walls 44 or inner walls 30a changes from a smaller to a larger one. The term "inward" refers to the opposite relationship (i.e., a relationship in which the distance between the walls 44 or the inner walls 44a changes from larger to smaller).

Figures 1A and 1B show one embodiment of the channels 36 in which the walls of the channels 36 are interconnected. 97552 58 dense parallel. Figures 2-4 show a preferred embodiment of the present invention, in which the conduits 36 form the interior of the walls are inwardly inclined from the top surface 34 of the framework 32 of the framework 32 toward the bottom surface 35. When the walls 44 of the chickens 5 are tilted either inwardly or outwardly, the inner walls 44a of the lattice 32 have the opposite relationship to each other. As shown in Figures 2-4, when the walls 44 of the channels 36 are inclined inwardly from the upper surface 34 of the truss 32 toward the lower surface, the inner walls 44a are thus inclined outwardly from the upper surface 34 of the truss 32 toward the lower surface 35. The inclination of the walls 44 and the inner walls 44a is controlled by collimating the light used to cure the photosensitive resin.

The grid 32 of the inner walls 44a are preferably out to a 15 feet inclined grid 32 from the upper surface 34 of the framework 32 to the bottom surface 35 toward an extent that the paper side network 34a of surface area of less than about 70% of the framework 32 of the total surface area of the reticle 32 in the second surface 35 of the backside network The area 35a is at least about 20 45% of the total area of the lattice 32. In a particularly preferred embodiment, the interior walls 44a are tapered such that the paper side network 34a surface (first surface knuckle area AK1) is approximately 35% of the total surface area of the backside network 35a 25 surface (second surface knuckle area AM2) is about 65% the papermaking belt of the present invention, the back side 10 of the total surface area prior to the formation of the passageways 37 in the backside network 35a. In this particularly preferred embodiment of the invention, the conical angle, αT of the walls 44 of the channels 36, in Figure 21, is about 15 degrees with respect to the vertical.

Figures 3 and 4 show the relationship between the lattice 32 and the reinforcing structure 33. As shown in Figs. 3 and 4, the reinforcing structure 33 is generally located 35 closer to the back side of the papermaking belt 10 than the paper contacting side 11. Although it is possible to form a belt in which the reinforcing structure 33 is placed closer to the paper side 11, such a structure is not preferred.

There are three main reasons why the reinforcing structure 33 is placed closer to the back side of the papermaking belt 10. One reason is that the reinforcing structure 33 is generally placed against the casting surface during formation and, as a result, only a limited amount of resin is generally present between the reinforcing structure 33 and the casting surface 10. Another reason is that it is often advantageous for the reinforcing structure 3 to act as a tread, i.e. a machine in contact with the machine, when the resin grid portions on the back side 12 of the papermaking belt 10 wear thin because the reinforcing structure 33 provides a more durable surface contact with the cured 32 with the papermaking equipment over which the papermaking belt 10 passes. The final reason is that a portion of the resin framework 32 covering the reinforcing structure 33 is of efficient design and a depth of 20 per 33 paper of the desired types of channels 36 to form the reinforcing structure 51 on the surface side. The portion of the resin lattice 32 covering the reinforcing structure 33 is referred to as "overload" and is denoted tc in Fig. 21. This overload 25 allows the channels 36 to properly perform their function of providing an area into which the fibers in the paper web can be directed. without interfering with the strands of the reinforcing structure 33.

When it is said that the reinforcing structure 33 is placed closer to the back side 12 of the papermaking belt 10, these dimensions may vary. In a preferred embodiment of the papermaking belt 10 of the present invention, a typical preferred woven element 35 having overlapping warp threads has a thickness of about 0.254 mm to 0.94 mm • 97552 60 (10 to 37 mils). The thickness of the resin overload tG is about 0.102 to 0.672 mm (4 to 30 mils). When the overload tc is in the preferred range, the thickness of the composite papermaking belt 10 is generally about 0.356 to 1.70 mm (14 to 67 mils).

5 Some applications may require an overload t0 thickness of about 0.051 to 6.35 mm (2 to 250 millimeters). This would, of course, change the overall thickness of the composite papermaking belt 10 accordingly.

j

Figures 3 and 4 show the 35 distinctive features of the second surface of the papermaking belt 10 of 10 background side 12 and the grid. As shown in Figures 3 and 4, the papermaking belt 10 has a textured backside 12.

It is this textured backside 12 which is also referred to herein as "backside texturing", or "rear side 15 texture", is very important in the context of this invention.

The term "texture" as used herein with respect to the papermaking belt 10. The backside 12 of the means 12 to the characteristic of the backside, created by discontinuities or nonplanar interruptions in an ordinarily smooth-20 ace or planar surface. These discontinuities, i.e., non-planar breaks, may comprise protrusions from the plane of such a surface or recesses in such a planar surface.

Figures 22A to 22C show that the texture of the backing surface 25 can be provided by different parts of the papermaking belt when the belt comprises a lattice and a reinforcing structure.

However, it should be understood that Figures 22A - specific set 22C backside texture types will not necessarily occur according to the present invention paperinval-30 mistushihnassa 10. The particular backside texture of a type that is likely to form a papermaking belt of the present invention is illustrated in Figures 3, 4, 11A, 11B, and in some of the other later figures.

Figures 22A - 22C show that a backside texture 35 can generally be achieved by the passageways 37, JOT 97 552 61 ka pintatekstuurln form the irregularities 32 of the second surface 35 of the framework 38 in the backside network 35a; each of the reinforcing structure 33, side 52 of the distinctive features of both pintatekstuurln 5 or irregularities forming passageways that each of the reinforcing structure 33, side 52 of the distinctive features of. These terms are defined and 52. The characteristics of each of the reinforcing structure 33 side will be described below. Each of the 10 alternative ways to provide a background texture is then considered with reference to Figures 22A-22C.

As used herein, the term "passageways" means spaces through which air may pass. The term "passageways" is not to be construed to include spaces of a particular shape and size. Thus, the passageways 37 described herein are not limited to spaces resembling tunnels or the like.

As used herein, the term "surface texture irregularities" (or simply "irregularities") means any discontinuity or non-planar breakage in a normally smooth or planar surface, such as protrusions from a smooth surface plane and / or depressions in such a surface. The irregularities 38 comprise those portions 25 which form the irregular or uneven portions of the framework 32 of the second surface 35 in the backside network 35a. Pintatekstuurln the irregularities 38 can be any discontinuities, or breaks in the hartsimateriaa-glycol, which forms the backside network surface 35a, 30 or any of the backside network surface 35a from which there is removed from the resin or with a resin is placed into the network surface 35a.

Figures 22A - 22C are shown in each of the reinforcing structure 33 of the machine of the characteristic features of the side 52, that side may form the backside texture or - 97 552 62 contribute to form. As shown in Figures 22A - 22c are shown, the structural components 40a such as the knuckles of a woven reinforcing structure and the yarns defining a number of levels, which are references for describing the backside 10 of the belt 5 of the texture. The back side 12 of the papermaking belt 10 of the present invention defines a plane from which the designation Pb is used. Defined by the backside of the belt Pb level is the level which would be in the same plane as the flat surface, if the papermaking belt of the present invention, October 10, the backside 12 placed on a flat surface. 33 for the paper side 51 of the reinforcing structure knuckles (such as paper side knuckles such as 105bl) define a plane which is designated Pkl. Pkl level is referred to herein as "paper reinforcing structure 15 to be determined by the level of Party". of each of the reinforcing structure 33 of the machine side knuckles 52 (such as konepuo-len knuckles such as 105b2) define a "for the reinforcing structure to be determined by a half of the 20-period" a plane which is designated Pk2 «** level of k2 is referred to herein.

As shown in Figures 22A, 22B and 22C, the cross-section 33 of the reinforcing structure of the machine-facing side 52 of the profile has a contour shape that is determined. As shown in these figures, of the woven reinforcing structure 25 trans-33 products per side 52 of the contour is defined by some of the warp yarns 52 and some of the weft yarns 54 (which comprise the reinforcing structure 33. The structural components 40a). In addition, Figs. 22A, 22B and 22C show that portions of some warp yarns 54 and some weft yarns 54 on the machine side 52 of the reinforcing structure 33 form protruding portions 120. As used herein, the term "protruding portions" refers to portions of warp yarns or weft yarns or other structural components 40a. which the machine 33 per the reinforcing structure 35 and the side 52 are located inwardly of the reinforcing - 97 552 plane defined by the machine-facing 63 side of the structure Pk2.

the levels used in the above-described and the shoulder portions 120, the term "inward" refers to either a 5 papermaking belt 10. The paper side 11 and the papermaking belt 10 from the backside of the papermaking belt per 10 to the center (ie. the paper side 11 and the backside, between 12 in the middle for passing an imaginary line). In relation to the planes described above, the term "outward-10" means from the center of the papermaking belt to either the paper side 11 of the papermaking belt 10 or the backing side 12 of the papermaking belt 10. In Figures 22A-22C, the raised portions 120 are shown to be formed of warp yarns 53 and weft yarns 54 on the machine side 52 between machine side knees, such as knees 105b2.

In the preferred multilayer woven reinforcing structure 33 shown in Figs. 22a, 22B and 22C, the protruding portions 120 are generally formed of portions of the warp yarns 53 of the second warp layer 20 together with portions of the interwoven weft yarns 54. More specifically, a preferred reinforcing structure 33 form raised portions 120 are in the second warp layer D of warp yarns 53 parts and 54 parts of the weft yarns, which are the 25 and 33 for reinforcing structure of the same machine side knuckles of the threads 1052 formed between the parts. As 22D is shown in the figure, when the reinforcing structure 33 comprises a cross-section of round yarns, and yarns soles of the plane Pk2, drinking-30 coat the raised portions 120 will be formed in addition to parts of the wires of pages which, because the yarns cross sectional curvature differ for the reinforcing structure to the plane defined by the side of the PM 2. They are referred to as "raised peripheral portions" and are designated 120a 35 in Figure 22D. Fig. 22D shows that in the cross section shown in the cross section 97552 64, these raised circumferential portions 120a are located in the region of the projections A1 of the warp surfaces of the warp yarns 53 in the second warp layer D.

Figures 22A - 22C also show that certain co-5 houmaosat, the inwardly-spaced raised portions 120 ', are located more inwardly of the reinforcing structure of the machine-facing side of the plane defined by Pk2 than other raised portions. Figs. 22A to 22c show that in the preferred multilayer reinforcing structure 33, the cross section shown in Figs. 10 is assumed to be formed by some of the inner protruding portions 1201 in the second warp layer D. Figs. 22A to 22C show that the dots forming the base 53 'of these warp yarns form a "protruding surface" 15 defining a plane Pr. The plane Pr can also be called the plane defined by the protruding portions forming the protruding surface.

With respect to the drawing figures, it should be noted that the distance of the second warp layer D of warp yarns are the machine 20 of the reinforcing structure toward the plane defined by the side of the PM 2, is for purposes of illustration somewhat exaggerated in the figures 22A - 22C and in some other figures. It should be understood that in some variations of the reinforcing structure 33, these warp yarns may be at different distances inwardly from the plane. As shown in Figure 22D illustrated a variation of the reinforcing structure 33, the warp yarns of the second warp layer D may even be of the reinforcing structure of the machine-facing side of the plane defined by the PM 2. In the case mentioned, they are not located inwards at all.

Alternative ways of identifying characteristics of the passageways 37, the surface texture irregularities 38 each and the machine side of the reinforcing structure can generally be formed with the backside texture-35 execution, shown in Figures 22A - 22C. One of the ways.

97 552 • 65 to the papermaking belt of the present invention, the back side 10 texture 12 can be provided is shown in Figure 22A. 22A, the texture is provided entirely by the passageways 37 that provide surface texture irre-5 homogeneities network 38 of the framework 32 to the backside 35a. 22A is shown in Figure 32 of the second surface 35 completely covers the reinforcing structure 33 when the backside texture 12 is provided entirely by the passageways 37 and the irregularities 38. While this type of texturing 10 can be formed using methods other than the method described herein, it generally does not arise in the manufacture of a papermaking belt using this the method described.

As used herein in reference to the surfaces of the lattice 32, the term "cover" means that said side of the reinforcing structure 33 is located entirely between the first and second surfaces 34 and 35 of the lattice 32. The surfaces of the lattice 32 are considered herein to "cover" that side of the reinforcing structure 33 when positioned in that manner, although there are portions of the reinforcing structure 33 within the channels 36 which do not have resin material on either side thereof.

As shown in Figures 22B and 22C shows the backside texture can be provided partially by the passageways 37 and irregularities 38 and 25 partially towards the reinforcing structure 33 of the machine-facing side 52 of the contour. Fig. 22B shows one alternative situation in which the second surface 35 of the lattice 32 generally does not cover any parts of the reinforcing structure 33, so that the machine-facing side 52 of the reinforcing structure 33 is exposed. Fig. 22C shows another alternative situation in which the second surface 35 of the lattice 32 covers parts of the reinforcing structure 33 on the machine side 52 and leaves the other parts of the reinforcing structure 33 exposed.

- 97552 66

Figures 22A - The types of backside texturing shown 22C are the three basic backside texturing type. These types of backside texturing is called for convenience as "positive backside 5 texture"; "Negative backside texture" and both "positive and negative backside texture" combination.

such as that shown in Figure 22A 's positive backside texture ", it is meant that the running paths 37 and 10 extend from the plane defined by the backside 10 of the belt Pb for reinforcing the structure of the machine-facing side of the plane defined by the PM 2. As shown in Figure 22A, the texture is positive for the reinforcing structure involved in the plane defined by side 15 is inwardly PM 2 level, which is determined by the papermaking belt Pb background. Thus, the reinforcing structure 33 is located entirely between the first surface 34 of the lattice 32 and the second surface 35 of the lattice 32.

Another, and perhaps an easier way of looking at Positiv-20 from the backside texture is to look at the passageways 37 and irregularities 38 and the reinforcing structure for the machine of the relationship between the PM 2 between the plane defined by side rather than the relationship, the passageways 37 and surface texture irregularities 38 in the paper ready-to-25 tushihnan the back of the plane defined by the Pb. 22A, in the case of positive backside texture such as that of the passageways 37 are positioned outward of the plane Pk2, which is defined by the machine-facing side of the reinforcing structure. The surface texture irregularities 38 of dimension 30 outward from the machine-facing side of the reinforcing structure of the plane defined by the PM 2.

such as that shown in Figure 22B "negative backside texture", it is meant that the passageways 37 extend inwardly from the machine of the reinforcing structure 35 toward the plane defined by the side towards the plane PM 2 97 552 67

Pkl, defined by the paper-facing side of the reinforcing structure. Exclusively negatively textured, the papermaking papermaking belt backing side of the plane defined by Pb, and the reinforcing structure 5 towards the plane defined by the side of the PM 2 are the same thing.

such as a "positive and negative backside texture", as shown in Figure 22C, it is meant that the presence of the passage of each type described above. Thus, some of the passageways 37 are positioned in the machine 10 for the reinforcing structure to the plane defined by side Pk2 and some of the passageways 37 are positioned outward of the reinforcing structure of the machine-facing side of the plane defined by. The positive and negative backside texture in the case of the reinforcing construction 15 Coffee machine-facing side of the plane defined Pk2 lies inward of the plane defined by the papermaking backside of the belt Pb.

on the basis of three figures discussed above analysis it is apparent that a variety of the backside 20 the text-containing papermaking luck types of tread is different.

As shown in Figure 22A, track belts which have a positive backside texture, the tread consists of (at least initially) in whole resin material. After 25 and surface texture irregularities 38 form pyälle-fill in the projections extend over the machinery employed in the papermaking, these projections will tend to wear off of the belt 10 after the number of revolutions, so that at some point the wear surface will become virtually the same as that for the machine 30 of the reinforcing structure of the side of the plane defined by the PM 2. The new wear surface comprises a side 52 and the ground plane PM 2 past the grating 32 from a combination of the resin in the layer 33 of the reinforcing structure. At this point, there is a very limited number of passageways 37 along which 97552 68 air can pass through the surface 35 of the grid 32.

As shown in Figure 22B, belts having a negative backside texture, the original five-wear surface generally consists solely of the reinforcing structure 33 of the machine-facing side 52 of the parts. In the case of negative texturing, the original tread thus consists of polyester (or some other material as defined above), which is generally more durable than the resin material forming the grid 32. As shown in Figure 22B, negatively textured belts may further have passageways, such as 37 'extending inwardly from the machine-facing side 52 of the reinforcing structure 33. As the belt wears so that the tread coincides with the machine-facing side 52 of the reinforcing structure 33, these passageways 37' further provide openings in the rear side 12 of the belt. Thus, belts having a negative backside texture, usually kuluttuaan allow the escape of air 20 continues to some extent across the reverse side 12.

As shown in Fig. 22C, in belts having a combination of both negative and positive texture, the tread consists at least initially entirely of a resin material forming a grid 32. As the knurled protrusions comprising this resin material wear away, the tread becomes, as in Fig. 22A of the belt is concerned, in fact, the same as the reinforcing structure toward the plane defined by the side of the PM 2. However, one difference between the belts shown in Figures 22A and 22C is that due to the negative texturing, the latter belt still has passageways 37 after the positive texture has disappeared. For this reason, it is contemplated that it is generally preferred that the embodiment of the present invention have at least some negatively textured texture to retain the textured tread on the backside after the original texture has been removed.

In the present invention, the texture is formed on the back side of the paper-5 manufacturing belt 10 by exposing the liquid photosensitive resin with light having an activating wavelength through the reinforcing structure 33. The first part 40 of the reinforcing component Poi prevent parts of the light-sensitive hartsimate riaalista to cure, wherein the second surface 32 of the grid October 35 in the backside network 35a formed by the passageways 37 and surface texture irregularities. The location, characteristic properties, and distribution of the passageways 37 and irregularities 38 in the papermaking belt are therefore generally described in relation to the reinforcing structure 33.

15 A few terms are defined which serve as references to describe the location, characteristics and distribution of the pathways 37 and the surface texture irregularities 38 in relation to the reinforcing structure 33.

As shown in Figures 12 and 12Ά, both the paths 20 37 and the surface texture irregularities 38 determine the projections of the surfaces. It will be appreciated that the passageways 37 and surface texture irregularities 38 are shown in a manner in Figures 12 and 12A for further processing and that the types of passageways 37 and irregularities 25 38 shown may not be present in all embodiments of the papermaking belt of this invention. The projection of the surface of the passageways 37 shown in Figures 12 and 12A is represented by the letter designation Ap. As used herein, the projection of the surface of the passageway 37 means the area defined by the projection of the passageway 37 in the z direction. The projection of the surface 38 of the irregularity 38 shown in Figures 12 and 12A is represented by the letter At. As used herein, the surface projection of the surface texture irregularity 38 means the area defined by the projection of the irregularity 38 in the direction 35 z.

- 97552 70

In this description, when the surface projection 38 or surface texture irregularity 38 (or the surface projection of the surface texture or surface texture irregularity 38) is described as being "in line", "inside" or "located inside" or other similar terms in relation to some reinforcing structure 33 (or grid 32) of the surface projections of the elements, it is meant that the path or irregularity is within the boundaries of the surface projection at all planes to which that element could be projected in the z direction. In other words, the path or irregularity "within" the surface projection could be located above or below the surface projection determining element or even partially above and partially below that element. In addition, parts of the pathway or irregularity could be in one or more planes on which the element in question is projected in the z direction.

Figures 12 and 12A show some possible locations for the passageways 37 and surface texture irregularities 38 described above. Referring to Figures 12 and 12A, from left to right, the first passageway 37 shown is partially within the warp surface projection A1. Part of this passage 37 is also on the outer side of the warp surface projection A, ^. On the right side of the first passageway 37 there is an irregularity 38. The irregularity 38 shown in Figs. 12 and 12A is within the projection A 1 of the warp surface. To the right of the irregularity 38 is a third passageway 37. The third passageway is entirely within the projection of the pore surface A ^ 30. The fourth path 37 is shown to the right of the third path 37. The fourth passageway 37 is entirely within the warp surface projection A1.

It should be understood that when the path 37 or surface texture irregularity 38 is described relative to the projection of the surface 35, this means that the element in question is distributed in a generally defined manner with respect to the projection of the surface. However, there may be small portions of the path 38 or irregularity 38 that do not exactly correspond to that area. These slight shifts in the actual position of the element from the surface projections can be due to at least two factors. One factor is that these elements (such as paths and irregularities) are extremely small and very small changes in the position of the element grow disproportionately large 10 relative to the projections on the surface. This can cause the element to be slightly outside the boundaries of the surface projection. Another factor is that the positions of the pathways 37 and the surface texture irregularities 38 are sometimes obtained in such a way that the light rays which cure the liquid photosensitive resin forming the lattice 32 pass through the reinforcing structure 33. The direction of travel of these light beams is not always exclusively in the z direction, and as a result, the projection of the areas described above from the direction of the light source may be slightly different from the projection of the same areas in the z direction.

The characteristic features of the passageways 37 and the surface texture irregularities 38 are best discussed with reference to Fig. 21. As shown in Figure 21, there is a relationship between the passageways 37 and the surface texture irregularities 38. The passageways 37 are openings for the passage of fluids or, more specifically, air or air and water along the second surface 35 of the grid 32. Kuntaus-counterpart network 35a formed by the passageways 37, they provide the surface texture irregularities 38. The EPA 30 regularity 38 are, therefore, 35a of portions of the framework 32 of the backside network, which surround the passageways 37. In the general sense, walkways themselves 37, however, provide surface texture irregularities because they are also discontinuities or irregularities in the framework 32. purity-35 counterpart network 35a.

97552 72

As shown in Figure 21, both the passageways 37 and the irregularities 38 differ from the passages 36 passing through the grid 32. By "distinct" refers to channels that the passageways 37 and the irregularities 38 which 5 form deviations of the framework 32 otherwise silestä and continuous backside network 35a, it is separated from the channels 36 formed through the holes 41. 26 formed by holes in channels 41 is therefore not meant to categorize the passageways or surface texture irregularities.

Figure 21 shows the physical characteristics of the individual passageways 37. It is to be understood that Figure 21 is an exaggerated schematic view of part of the papermaking belt which shows a range of different shapes of passageways 37 and surface texture irregularities 38. Although shown in Figure 15 21, selection of the backside texturing is used tökelpoinen shooting 38 of the general characteristic features of the passageways 37 and irregularities, non Figure 21 raised by the explicit backside texturing may not actually be present in accordance with the present invention, Sessa 20 papermaking belt 10. the papermaking belt particular backside texturing depends on the method used to make the belt. These particular textures are generally discussed herein and in describing a method of making the papermaking belt 25 of the present invention. valmistusmenetel system after the description of the papermaking belt treated with a representative papermaking belt prepared in the backside texture of the belt of one of the methods mentioned in connection with magnified photographs of the.

As shown in Figure 21, the passageways 37 may have sides, generally designated 66. These sides may have an unlimited number of different shapes. They may be curved or relatively straight in cross-section or partially curved and partially straight. Often, however, the sides 66 of the passageways 37b of 97552 73 are so irregular that they cannot be precisely defined.

As shown in Fig. 21, the sides 66 of the passageways 37 may extend from relatively vertical (i.e., 5 z oriented) to relatively horizontal (y and x oriented) sides. The angle formed by the side 66 with respect to the z direction is denoted by a in Fig. 21. However, it should be understood that in the case of a curved or irregular path 37, the size of the angle α varies depending on the reference points used to measure the angle a.

In addition, each passageway 37 may have different numbers of different sides 66. The number of sides 66 may vary from a substantially continuous continuous curved wall to a virtually unlimited number of different cross-sectional sides. In the simplified cross-section shown in Fig. 21, some of the passageways 37 appear to have sides 66 resembling inner walls, sides 66a. In addition, some of the passageways 37 with relatively vertical walls 66a have a side resembling a roof, 66b. However, one side of the lane 37 is always open. Open pages are denoted by 66c in Figure 21.

In addition, although the passageways 37 are generally extremely small, they have a predetermined height hp, a width wp, a distance of 15 s apart from each other sp, and a cross-sectional area A ,,,.

As shown in Figure 21, the height hp of a passageway is the distance measured in the z direction the plane defined by the backside of the belt Pb to a point, such as 66d, which is a passageway 37 of the inner surface. As shown in Fig. 21, the height hp of the different parts of the individual path 20 may vary in the width direction of the path 37. In addition, the second surface 35 of the backside network 35a of the various passageways 37 in the height hp can vary from passageway to passageway.

- 97552 74

The width wp of the passageway 37 is the distance between two points on the opposite side walls 66a of the passageway 37 measured in some direction in the X-Y plane according to the selected cross section. If one curved surface forms 5 side walls, the width wp of the passageway is the distance between two points on opposite sides of the curved surface, measured in the X-Y plane. As shown in Fig. 21, the width of the different portions of a single path may vary depending on which portion of the path 37 the width is measured. In addition, 10 of the second surface 35 of the backside network 35a of different width of the passageways 37 can vary from passageway to passageway.

Route cross-sectional area represented by a hatched area in Figure 21. The route cross-sectional area A "is the route poikkileikkauk inner portion 15 of its surface area which defines the inner part of the backside of the belt Pb extending in the plane defined by an imaginary line. The total cross-sectional area ApT of the individual passageways 37 is important because it is through these areas that air escapes as the papermaking belt 20 of the present invention passes over the suction box during papermaking.

Distance between parallel passages 37. represents the letter sp in Fig. 21. The distance sp between the parallel passageways 37 is defined here using two reference points on the sides of the irregularities 38 bounding the passageway 25 in question. These two points, denoted by 109 in Fig. 21, are on the sides of the irregularities 38, referred to herein as the adjacent sides of the irregularities 38. 38 neighboring sides of the irregularities of which is designated 30 67a is referred to as such because they also form the ester nakkaisten passageways 37 pages 66. The selected two reference points 109 are the neighboring sides 67a in points that are in the z direction as measured closest to the backside of the belt-set value Pb. In Fig. 21, these two reference points 109 are in fact in the plane Pb, but - 97552 75 this is not always the case. The distance sp between the parallel passageways 37, shown by the arrow in Fig. 21, is the distance measured in the X-Y plane between the reference point 109 on the adjacent side 67a of the irregularity 38 between these passageways and the next reference point 109 on the opposite adjacent side 67a of the same irregularity 38.

The overall model of the distances between the passageways 37 determines the distribution of the passageways 37. The passageways 37 may be 10 distributes unlimited number of different ways to network the framework 32 to the back side 35a. The distribution of the passageways 27 can be, for example, random, uniform, regular or according to a certain pattern.

One example of paths 37 at random distances 15 is the paths 37 of a belt 10 comprising a combination of positive and negative texturing, shown in Figure 22C. As used herein, the term "uniform" means that the density (i.e., number) of passageways 37 is approximately the same over the entire surface, even if passageways 37 do not form any particular pattern. As used herein, the term "regular" means that the spacing between adjacent passageways sp is approximately the same across the entire backside network 35a. One example at regular intervals of the passageways 37 will have a positive-25 ously backside texturing with the belt 10 of the passageways 37 which are shown in Figures 3 and 4. The belt 10 by the Figures 3 and 4 also serves as an example of uniformly-spaced passageways in that the density of passageways is approximately the same backside network 35a over the entire surface.

The distance between the parallel passageways 37 of the belt shown in Figures 3 and 4 is sufficiently similar that the distances between the passageways 37 shown therein can also be considered to follow the pattern.

The passageways 37 may also be distributed in "generally" all parts of the second surface 35 of the grid 35 32.

76 - 97 552 This means that any portion 35a and the passageways 37 can be found in the backside network surface does not exist in one or more of the backside network surface 35a of the area from which the passageways 37 are not provided.

5 In the case where the reinforcing structure comprises a woven element, the passageways 37 can thus be located in the projection A „of the reinforcing surface of the reinforcing structure or in the projection Aq of the open surface. By defining that the breakdown has occurred "in general, the whole" backside network 10 35a and the "size" of the backside network, means that, while the passageways 37 can be found in virtually any laid down in the backside 35a, see the Network, the passageways 37 do not necessarily cover the entire network of the backside 35a.

Figure 21 shows the physical characteristics of the individual irregularities in the surface texture. Surface texture irregularities are further described generally in Broadston, Mark's Standard Handbook for Mechanical Engineers, Surface-Texture Design, Production and 20 Control, McGraw-Hill 1967, pp. 13 - 106 - 13 - 112, which. is incorporated herein by reference. As shown in Fig. 21, the sides 67 of the surface texture irregularities 38 are commonly referred to as 67. The surface texture irregularities 38 of the present invention may (as well as the wefts) have sides 67 having an unlimited number of different shapes. As with the passageways, the sides of the irregularities 38 may be curved or relatively straight when viewed in cross section, or partially curved and partially straight. However, the pages 67 30 of the irregularities 38 are often so irregular that they cannot be precisely defined.

As shown in Fig. 21, the sides 67 of the irregularities 38 may extend from relatively vertical (i.e., extending in the z direction) to relatively horizontal (extending in the x and y directions). The angle whose irregularity - 97552 77 den 38 side 67 with direction z is denoted by a ± in Fig. 21. However, it should be understood that in the case of irregularity 38 having curved or irregular sides, this angle depends on the reference points. , which are used to measure the angle af formed by the page 67 of the irregularity 38.

In addition, each irregularity 38 may have varying numbers of different pages 67. The number of pages 67 may vary depending on the shape of the irregularity 38. 10 For dome- or knob-shaped irregularities, the page (s) 67 of the irregularity 38 appear (appear) as a single continuous curve as a line when viewed in cross section. In cases where the irregularity 38 has a more complex shape, there may be a virtually unlimited number of pages 67 of different cross-sections.

Fig. 21 shows the adjacent sides 67a of the irregularities 38 described above formed by the inner walls 66a of the passageways 37. As shown in Figure 21, these adjacent sides 67a are often relatively different in length, because adjacent sides 67a of a given irregularity 38 may be formed by the side walls 66a of two or more radically different paths 37.

Figure 21 also shows that one or more of the sides 67 of the irregularities 38 may not be formed of the same structure that forms the walls of the adjacent passageways 37. These pages are referred to as the independently formed pages of the irregularities 38 and are denoted 67b in the drawings. Often, these independently formed sides 67b of the irregularities 38 form part of the tread on the back side 12 of the belt 10.

In addition, as with the passageways 37, although the irregularities 38 are generally extremely small, they also have a limited height hif width wt, distance and cross-sectional area Axl. As shown in Figure 21, the adjacent sides 67 of the irregularities 38 often form the boundaries of the irregularities 38. Since the adjacent sides 67a of the irregularity 38 can be quite different, it may be difficult to express the exact height of the irregularity 38 as well as the width and cross-sectional area Axl.

To define these characteristic features of the irregularities 38, a random 10 but uniform point is selected for taking these dimensions. This reference point is denoted by 110 in Fig. 21. The reference point 110 is the point which is the shortest of the adjacent sides 67a of the irregularity 38. More specifically, it is the shortest of the coterminous sides 67a of the point 15 which is the greatest distance inward from the plane defined by the belt track-side Pb. Figure 21 shows that point 110 may be at two different locations in the case of adjacent irregularities 38.

As shown in Fig. 21, the height h * of any point of the irregularity 38 20 is the distance measured in the z direction from the plane passing through the reference point 110 of that irregularity 39 to the point of the irregularity 38 of interest. As shown in Fig. 21, the height ht of the various portions 25 of the individual irregularity 38 may vary in the width direction of the irregularity. In addition, the backside network 35a of the various irregularities 38 of a height ht can vary from irregularity to irregularity.

The width of the irregularity 38 is the distance between the two points on the opposite sides 67 of the irregularities 30, measured in either the x or y direction, or in a direction between them in the X-Y plane, depending on the cross section used. If the sides 67 are formed by a single curved surface, the width of the irregularity 35 is the distance between two points on opposite sides of the curved surface, measured in the X-Y plane. As shown in Fig. 21, the width wA of the various portions of a single irregularity 38 may vary depending on which portion of the irregularity 38 the width is measured. Lisak 5-si backside network 35a of the various irregularities 38 of a width w can vary from irregularity to irregularity.

Irregularity of the cross-sectional area Axi is also shown cross-hatched area using Figure 10 21. The cross-area reference point 110 to the imaginary straight running, and a belt back side of the plane defined by Pb, the intermediate portion 38 of the irregularity of the surface area measured laid down in the cross section.

15 Irregularities 38 also have a distance s ± between parallel irregularities 39. As shown in Fig. 21, the distance of the irregularities 39 in a given direction s1 is the distance measured in the X-Y plane between one reference point 109 20 on the adjacent side of the irregularity 38 and a reference point 109 on the nearest neighboring side 67a of the next irregularity 39.

The overall pattern of the intervals between the irregularities 38 determines the Distribution of the irregularities 38. As well as walkways irregularities 38 may be distributed in an unlimited number of 25 different ways to the grid 32 in the backside network. The distribution of irregularities can be random, uniform, regular, or according to a certain pattern. As used herein, the term "uniform" means that the density (i.e., number-30) of the irregularities 38 is approximately the same over the entire surface, even if the irregularities 38 do not form any particular pattern. As used herein, the term "regular" means that the spacing between adjacent irregularities s * is approximately the same across the entire backside network 35a. 35, the passageways 37 in the case of irregular - 97 552 80 heap 38 may be distributed across the backside network "generally all" portions. When the irregularities 38 are distributed across "generally all below" the backside network 35a, it is meant that 5 while the irregularities 38 can be found, virtually virtually anywhere in the backside network 35a, the irregularities 38 do not necessarily cover the entire backside network 35a. Examples of the different distributions of the irregularities 39 are shown in the figures of the accompanying hidden drawings, which show the corresponding distribution types of the passageways 37.

In addition, the irregularities 38 of the features described above, they may be described in the framework 32 in the backside network 35a 15 as being projections or recesses. If the irregularity 38 is referred to herein as either a protrusion or a recess, the frame of reference used to describe the irregularity 38 is a plane Pk2 defined by the machine-facing side of the reinforcing structure. Any irregularity 38 that extends 20 outward from this plane in the z direction is a protrusion. Any irregularity 38 located in the z direction inward from the plane pk2 is a recess.

the papermaking belt 10 of the present invention, a preferred embodiment of the textured backside 12 of different properties possessed 25 depend on the method used to make the belt 10. When the belt is provided with a backside texture by exposing the photosensitive resin through light source of the reinforcing structure 33, as described herein, the backside texture respective characteristi-30 also depends on the first part of the opaque PQ1 characteristics. The specific characteristics of a typical belt made by the method described herein are shown in the enlarged photographs of Figures 34A-34C and will be discussed in describing the method used to make the belt shown in Figures 35. However, there are certain 97552 81 general properties common to belts made by the method described herein. These characteristics are best described with reference to Figures 11A and 11B.

As shown in Figures 11A and 11B are shown, the passageways 5 are generally mainly in the first part of läpinäkymättämön P01 projection of the first projection area Ai · Figures 11A and IB also shows that the backside of the belt defined by the level of Pb and a reinforcing structure for items in the side of the plane defined by the PM 2, 10 are the same . In other words, the belt 10 is negatively textured. Figures 11A and 11B also show that the heights of the passageways 37 extend inwardly toward the reinforcing structure of the plane defined by the first half of the PM 2 PQ1 of the structural components 40a of the bottom 15.

It is believed that the problems that arose with previous back-smooth papermaking belts were due, at least in part, to the extremely sudden effect of suction pressure on the paper web as the previous 20 belts carried the paper web over the vacuum dewatering machinery used in the papermaking process. It is assumed that the previous smooth-backed papermaking belts actually formed a temporary barrier over these vacuum sources. When the guide channels of the papermaking belt of the previous type 25 were then encountered, the suction pressure was applied extremely abruptly to the fibrous web on top of the resin lattice. The sudden application of this suction pressure is believed to have caused the abrupt deflection of the highly mobile fibers in the fibrous web, which was sufficient to allow these moving fibers to pass completely through the papermaking belt. The difference in the guiding of the fibers of the fibrous web as the prior belt 10a and the papermaking belt 10 of the present invention are carried is schematically illustrated in Figures 23A and 23B and graphically in Figure 24.

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Fig. 23A shows putative events when prior papermaking belts 10a encounter a vacuum dewatering apparatus used in a papermaking process, such as a suction box 24. Fig. 23B shows putative events when an improved papermaking belt 10 according to the present invention encounters ), which is applied to the fibers of the elementary web 18 as the papermaking belts shown in Figures 23A and 23B pass through the vacuum gap of the suction rod 10.

Although each of the papermaking belts 10a and 10 shown in Figs. 23A and 23B, respectively, comprises a grid 32 having a first surface 34, a second surface 35, and a reinforcing structure 33, the belts differ 15 in that the back side of the belt 10 grid 32 on the second surface 35 network 35a is textured whereas the belt 10a of the framework 32 to the backside network 35a is smooth. However, it should be understood that there are numerous other differences (including, but not limited to, the shape of the channels and the type of reinforcing structure used) between the papermaking belt 10 of the present invention and the prior belts 20 that are not shown in Figures 23A and 23B. The purpose of Figures 23A and 23B is to show the differences in the operation of the belts resulting from the differences between their backs. For simplicity and clarity, other differences are therefore omitted from Figures 23A and 23B.

As shown in Figs. 23A and 23B, both belts 10a and 10 carry a primary web 18 (having individual fibers designated 18a) on the first surface 24 of their grid 32. In the figures, a portion of each belt 10a and 10 passes through one slot 24d in the suction box 24. The parts of the suction boxes shown also include a front surface, a suction box surface 24 (^ first encountered as the paper-35 manufacturing belts run in the machine direction (left to right 97552 83 in the figures) in the papermaking process, and a trace surface, a suction box surface 24c2. each of the surfaces 24cx and 24c2 further has an edge adjacent the upper surface of the vacuum gap 24d, such as the front surface edge 241 of the suction box and the edge 24b2 of the rear surface of the suction box. to the belts and elementary webs 18. The suction-10 pressure V removes some water from the elementary web 18 and directs and rearranges the fibers 18a of the elemental web into the channels of the grid 32.

It is believed that the framework 32 to the back side 35a of the flat nature of the network in Figure 23A is formed under a reduced-15 32 second surface nesulku the grid 35 and the suction box 24 leading surface 24cx between the point designated as S. When the belt 10a travels to the right, encounters the vacuum slot 24d, seal is suddenly broken, and the suction pressure V is suddenly applied to the elementary web 18. This causes the fibers 18a of the elementary web 18 20 to suddenly guide the channels 36 and some of the more mobile fibers, denoted 18a ', pass completely through the belt 10a and accumulate on the trailing edge 24bia of the suction box 24. 'eventually accumulates so much that they accumulate into lumps on the back surface 24c2 of the suction box and form ridges over which the papermaking belt 10a has to pass.

Since the belt 10, the backside 12 (particularly the framework 32. backside network 35a) are testuroitu, Figure 30, 23B instead of passageways 37 through which air can papermaking belt 10 of the back surface 12 and the suction box leading surface 24ct, whereby the framework 32 of the backside network 35a and vacuum box 24 leading surface 24cx the barrier is eliminated. This air input is shown schematically by 35 large arrows VL. As shown in Fig. 23B, the inlet VL of air 97552 84 allows the fiber 18a in the elementary web 18 to be guided more gradually. Little, if any, fiber passes through the papermaking belt 10 and accumulates at the trailing edge 24b2 of the suction box. In addition, it is believed that the papermaking belt shown in Figure 5, 23B, 10 textured backside network 35a may also serve a scrubbing or cleaning function to remove the suction box and the second edge 24bz may accumulate in the fibers.

2. Method for making a papermaking belt 10 As described above, the papermaking belt 10 may take various forms. Although the method of forming the papermaking belt 10 is irrelevant as long as the belt has the above-mentioned characteristics, certain methods have been found to be useful. 15 For background, a method of making a "guide member" (i.e., a "porous member") that does not incorporate the improvements disclosed herein is described in detail in U.S. Patent 4,514,345 ("Method of Making a Foraminous Member", Johnson et al., April 30, 1985). 20 This Johnson et al. the patent is incorporated herein by reference to the extent consistent with this description. One method of making the papermaking belt 10 of the present invention and some variations thereof will be described below.

One preferred embodiment of the apparatus that can be used to form the endless belt papermaking belt 10 of the present invention is shown schematically in Figure 25. To provide an overview of the entire apparatus for making the papermaking belt of the present invention, Figure 25 has been simplified to some extent. The following figures show the details of this apparatus, and particularly the manner in which the passageways 37 and surface texture irregularities 38 fas-35 dostetaan 32 of the second surface 35 of the framework backside compared 35a 97 552 85 retaliation. At this point, it should be noted that the scale of certain parts shown in the figures may be somewhat exaggerated in the following drawings.

The overall process shown in Figure 25 generally comprises coating the reinforcing structure 33 with a liquid photosensitive polymer resin 70 as the reinforcing structure 33 passes over a forming unit 71 (i.e., a "casting surface") 72. As shown in Fig. 25 et seq., The resin 70 "is applied to at least one side (and preferably to both sides) of the reinforcing structure 33 so that the coating 70 substantially completely fills the pore areas of the reinforcing structure 33 and forms a first surface 34 'and a second surface. 35 '. The coating 70 is distributed so that at least a portion of the second surface 35 'of the coating abuts the working surface 72 of the forming unit 71. The coating 70 is also distributed so that the paper-facing side 51 of the reinforcing structure 33 is located between the first surface 34 'and the second surface 35' of the coating. In addition, as shown in Fig. 27, the coating 70 is distributed so that portions of the second surface 35 'of the coating are located between the opaque first portion P01 of the reinforcing component 40 and the working surface 72 of the forming unit 71. Coating the part, disposed between the first surface 34 'and 33 for the paper side 25 of the reinforcing structure 51 forms a resinous overburden t0'. The thickness of the overload t0 'is adjusted to a preselected value. The liquid photosensitive resin 70 is then treated with light having an activating wavelength (light that cures the photosensitive liquid resin) from a light source 73 through a mask 74 having opaque regions 74a and transparent regions 74b, and a reinforcing structure 33. The parts of the resin which are shaded 35, i.e. protected from light, by the opaque areas 74 and the first part P01 of the reinforcing structure 33 do not harden under the influence of exposure. 97552 86 sesta. The other parts of the resin (unshaded parts, and parts whose hardening of the reinforcing structure 33 is allowed by the nocturnal part P02) harden. Then removed from the uncured resin to leave conduits 36 which pass 5 cured resin 32 through the passageways 37 that provide surface texture irregularities 38 in the purity-counterpart network 35a, at positions corresponding to 70 of the second surface of the coating 35 'of the portions of the reinforcing structure 33 The first part P01 has prevented hardening.

10 For convenience, the steps of the overall process are divided into a series of steps and will be discussed in more detail in the next reading. It is to be understood, however, that the steps described below are intended to assist the reader in understanding the method of making the papermaking belt of the present invention, and that the method described below is not limited to a particular number and order of steps. It is also possible to divide some of the following steps into two or more steps without falling outside the scope of the present invention.

First Step The first step of the method of the present invention is to obtain a forming unit 71 with a textured work surface 72.

The forming unit 71 shown in Fig. 25 has a work surface denoted by the number 72. In Fig. 25, the forming unit 71 is shown as a circular element, which is preferably a drum. The diameter and length of the drum are selected according to suitability. Its diameter should be large enough 30 so that the barrier film 76 and the reinforcing structure 33 do not warp unnecessarily during the process. Its diameter must also be so large that the distance traveled on its surface is sufficient so that the necessary steps can be carried out as the drum rotates. The length of the drum is selected according to the width of the papermaking belt 10 to be formed.

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The forming unit 71 is rotated by a conventional drive not shown in the figure.

Fig. 27 is an enlarged schematic view of one alternative version of the casting process shown in Fig. 25.

Figure 27 also illustrates for the first time that in a preferred embodiment of the method of the invention, a hard rubber cover 91, preferably about 2.54 cm (1 inch) thick, is placed on the forming unit 71.

The forming unit 71 is preferably covered with a barrier film 76 which prevents contamination of the work surface 72 with resin. The barrier film 76 also facilitates the removal of the semi-finished papermaking belt 10 'from the forming unit 71. The barrier film 76 can generally be of any flexible, smooth, planar material. The barrier film 76 can be made of a polypropylene, polyethylene or polyester film. The barrier film is preferably made of polypropylene and has a thickness of about 0.01 to 0.1 mm. It is also preferred that the barrier film 76 either absorb light having an activating wavelength or be transparent enough to allow 20 to enter the work surface 72 of such a light generating unit 71 which absorbs light. The barrier film 76 is also typically chemically treated to prevent the resin from adhering to its surface and also to ensure that the resin spreads evenly on its surface. This chemical treatment is preferably a corona treatment. In the corona treatment of the barrier film 76, an electric discharge is directed to the barrier film 76 before it is installed in the apparatus shown in Fig. 25.

As shown in Figure 25, the barrier film 76 is fed into the system from the barrier film supply roll 77 by unwinding it from the roll 30 and causing it to travel direction of the arrow D2 direction shown. After unwinding from the roll, the barrier film 76 comes into contact with the work surface 72 of the forming unit 71 and is temporarily forced against the work surface 72 by the means described below. The barrier film 76 travels with the forming unit 71 as the forming unit 71 rotates.

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Finally, the barrier film 76 is separated from the working surface 72 of the forming unit 71 and passes to the barrier film receiving roller 78, on which it is wrapped. In the method embodiment shown in Figure 25, the barrier film 76 is designed to be used 5 times, after which it is discarded. In one alternative arrangement, the barrier film 76 may be in the form of an endless belt running around a set of return rollers where it is cleaned and reused.

The forming unit 71 is preferably also provided with means 10 to ensure that the barrier film 76 remains in close contact with its work surface 72. The barrier film 76 may be attached, for example, by gluing to the work surface 72. Alternatively, the barrier film 76 may be attached to the work surface 72 by a vacuum applied through a plurality of adjacent small openings distributed on the work surface 72 of the forming unit 71. The barrier film 76 is held against the work surface 72, preferably by conventional tightening means not shown in Figure 25.

Second Step 20 The second step of the method of the present invention is to provide a reinforcing structure 33 for incorporation into a papermaking belt having certain elements and having certain characteristics (described below).

33 The general elements and char 25 of the reinforcing structure of the female characteristics are shown in Figure 27. Figure 27 shows that the reinforcing structure 33 is the paper-facing side 51, a machine-facing side of the paper-facing side 51 opposite side, interstices 39 and a reinforcing compo-30 component 40 which consists of several structural components 40a. The first part P01 of the reinforcing component 40 has a first opacity 0X, and the second part of the reinforcing component 40 has a second opacity 02 which is lower than the first opacity 0X. The first opacity 0X 35 is sufficient to substantially prevent curing of the photosensitive resin material 97552 89 when the photosensitive resin material is in its uncured state and the first portion is placed between the photosensitive resin material and the actinic light source 73. The second opacity 02 is such as to allow the photosensitive resin material to cure. The first part P01 determines the projection Alf of the first surface, a part of which is shown in Fig. 27.

As mentioned above, the reinforcing structure 33 is an element around which the papermaking belt 10 is formed. Any of the reinforcing structures described in the previous section of this specification may be used. The reinforcing structure 33 is preferably a woven multilayer fabric shown in Figs. 6-11, characterized by warp yarns vertically directly superimposed, 15 and wherein the first portion P01 comprises at least some of the warp yarns 53 in the second warp layer D.

Since the preferred papermaking belt 10 is in the form of an endless belt, the reinforcing structure 33 should also be an endless belt, since the papermaking belt 20 10 is formed around the reinforcing structure 33. As illustrated in Figure 25, the reinforcing structure 33 is arranged so that it extends in the direction of the arrow D around the return roll 78a up around the forming unit 71 and returns salts, 78b and 78c. It is to be understood that the apparatus used to make the papermaking belt of the present invention includes conventional guide rollers, return rollers, drive devices, support rollers, and the like, which are not shown in Fig. 25.

Third Step 30 The third step of the method of the present invention is to contact at least a portion of the reinforcing structure 33 on the machine side with the working surface 72 of the forming unit 71 (or more specifically, in the case of an illuminated embodiment, conveying the reinforcing structure 35 33 over the working surface 72).

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As mentioned above, it is preferable to use a barrier film 76 to keep the working surface 72 of the forming unit 71 free of resin 70. In this case, in the third step, at least a portion 52 of the reinforcing structure 33 is brought into contact with the barrier film in such a way that the barrier film 76 becomes between the reinforcing structure 33 and the forming unit 71.

The particular manner in which the reinforcing structure 33 is positioned relative to either the work surface 10 72 of the forming unit 71 or the barrier film 76 depends on the particular design of the papermaking belt 10 desired. The reinforcing structure 33 can be placed in direct contact with the barrier film 76. Alternatively, the reinforcing structure 33 may be placed at a distance from the barrier film 76. Any suitable means may be used to disengage the reinforcing structure 33 from the barrier film 76. For example, a liquid photosensitive resin 70 may be applied to the machine side 52 of the reinforcing structure 33 so that between the structure 33 20 and the working surface 72 of the forming unit 71. However, it is preferred to bring at least a part of the machine per 33 on behalf of the reinforcing structure 52 (e.g., the machine side knuckles) directly in contact with the forming unit 71 the working surface 72 (or the barrier film 76, if it is 25 VED). Other parts of the reinforcing structure 33, such as the protruding parts 120, are detached from the working surface 72 of the forming unit 71.

The fourth step

The fourth step in the method is to apply a liquid photosensitive resin coating 70 to at least one side of the reinforcing structure 30 33.

The coating 70 is generally applied in such a way that the coating 70 substantially fills the pore areas 39a of the reinforcing structure 33 (the pore areas are defined below). The coating 70 is also applied in such a way that it forms a first surface 34 'and a second surface 35'. The coating 70 is distributed in such a way that at least a part of the second surface 35 'of the coating 70 is located against the working surface 72 of the forming unit 71. The coating 70 is distributed in such a way that the side 51 of the reinforcing structure 33 facing the tail is located between the first and second surfaces 34 'and 35' of the coating 70. Coating the part, disposed between the first surface 34 'and each of 33 paper side 51 of the reinforcing structure forms a resinous overburden t c'. The coating 70 10 is also distributed in such a way that parts of the second surface 35 'of the coating 70 are located between the first part PQ1 of the reinforcing component 40 and the working surface 72 of the forming unit 71.

The photosensitive resins 15 suitable for coating the reinforcing structure 33 are easy to select from many commercially available resins. Resins that can be used are materials, usually polymers, that cure or crosslink under the influence of radiation, usually ultraviolet (UV) light. For further information on liquid photosensitive resins, see Green et al.

Photocross-linkable Resin Systems, J. Macro-Sci. Revs. Macro Chem. C21 (2) (1981-82) 187-273; Bayer, A Review of Ultraviolet Curing Technology, Pin Paper Synthetics 25 Conf. Proc., September 25-27, 1978, pp. 167-172; Schmidle, Ultraviolet Curable Flexible Coatings, J. of Coated Fabrics 8 (July 1978) 10 - 20. All of the above three publications are incorporated herein by reference. Particularly preferred liquid photosensitive resins belong to the 30 series of Merigraph resins manufactured by Hercules Incorporated, Wilmington, Delaware. One of the most preferred resins is Merigraph resin EPD 1616.

In a preferred method of carrying out the present invention, antioxidants are added to the resin to protect the finished papermaking belt 10 from oxidation and to extend the life of the papermaking belt 97552 92. Any suitable antioxidants can be added to the resin. Preferred antioxidants are Cyanox 1790, marketed by American Cyanamid, Wayne, New Jersey 17470, 5, and Iraganox 1010, manufactured by Ciba Geigy, Ardsley, New York 10502. In a preferred method of making the papermaking belt 10 of this invention, both antioxidants are added to the resin. The following amounts of antioxidants are added: Cyanox 1790 1/10, 10 1%; Iraganox 1010 8/10, 1%. Both antioxidants are added to protect the papermaking belt of this invention from a variety of oxidant species.

Any method by which a liquid material can be applied to the reinforcing structure 33 is suitable for applying the coating 70. As shown in Fig. 25, in the preferred method for carrying out the present invention, the liquid photosensitive resin is applied to the reinforcing structure 33 in two steps. The first step is performed at the point 79 indicated by the extruder mouthpiece 79. The first step is referred to as the "pre-filling step" because it is performed before the coating portion of the reinforcing structure 33 is brought into contact with the work surface 72 of the forming unit 71. In this first step, the first liquid photosensitive resin coating 25 is applied to at least the machine-facing side 52 of the reinforcing structure 33 by the extruder mouthpiece 79 so that the pore areas 39a of the reinforcing structure 33 are at least partially filled. The first coating preferably fills the pore areas 39a of the structure 33 of the reinforcing structure 30 completely. The pore areas are best seen in Figure 22D. As used herein, the term "void areas" (or "void volume") refers to all 33 of the reinforcing structure of the open spaces, which are the paper of the reinforcing structure toward the plane defined by the side and the Pkl per machine and borne by the lu-35 97 552 to determine the structure of side 93 between the level-PM 2 ( i.e., spaces between said planes that are not occupied by the reinforcing component 40). The pore spaces 39a thus comprise the pores 39a and any other open spaces between the planes Pk1 and Pk2.

Applying the resin 70 to the extruder mouthpiece 79 is associated with applying a second liquid photosensitive resin coating 70 in a second step by a nozzle 80 located near the point where the mask 74 is fed into the system. The nozzle 80 applies a second liquid photosensitive resin coating 70 to the paper-facing side 51 of the reinforcing structure 33. It is necessary to apply the liquid photosensitive resin 70 evenly across the width of the reinforcing structure 33 and force the required amount of material 39 wholly. The second coating is applied such that the first coating, together with the second coating, forms a single coating, a coating 70 having a first surface 34 'and a second surface 35' as described above and distributed as described above. Thus, this one coating 70 is distributed in such a way that at least a part of the second surface 35 'of the coating is located against the working surface 72 of the forming unit 71; the reinforcing construction 25 make the paper-facing side 51 positioned between the first surface 34 'and the second surface 35' of the coating and the portion disposed between the first surface 34 'and each of 33 paper side 51 of the reinforcing structure forms a resinous overburden t0'.

It will be seen from the drawings that the steps of applying the liquid photosensitive resin 70 to the reinforcing structure 33 may not always occur in time immediately after the third step described above. This means that the coating (as first stage 35 of the coating) is carried out before the reinforcing structure 33 KO per 97 552 94 52 Netta the side brought into contact with muodostusykslkön 71 with the working surface 72 and then, if you look at any specific part of the reinforcing structure 33 which passes through the reinforcing around the structure recovery lan 78a toward the forming unit 71. Looking at the apparatus assembly shown in Figure 25 as a whole, it will be appreciated that at least a portion of the endless belt comprising the reinforcing structure 33 would generally contact the machining surface 72 of the forming unit 71 before any coating of the reinforcing structure 33 occurs. However, as described herein, the method is generally viewed from the former perspective.

In the embodiment shown in the drawings, the second step of applying the light-15 sensitive resin (i.e., the "backfill step") occurs after the point at which the reinforcing structure 33 first comes into contact with the forming unit 71 as it passes around the return rollers of the reinforcing structure. It is to be understood that these two events (i.e., applying the coating and contacting the reinforcing structure 33 with the working surface 72 of the forming unit 71) could also be simultaneous or the photosensitive resin could be applied to the upper surface of the reinforcing structure (i.e., the paper side 51) before the point where the reinforcing structure 33 is first brought into contact with the forming unit 71. It is intended that the method of this invention include all configurations and sequences of the basic steps described herein. However, the coating of the reinforcing structure 33 preferably takes place in the order shown in the drawings.

Fifth Step The fifth step of the method of the present invention is to adjust the thickness tc 'of the overload of the resin coating 70 to a preselected value. In the preferred embodiment of the belt manufacturing apparatus shown in the drawings, this step takes place approximately at the same time, i.e. simultaneously, with the second step of applying the liquid photosensitive resin coating to the reinforcing structure 33.

5 The preselected value of the overload thickness corresponds to the desired thickness of the papermaking belt 10. This thickness also naturally depends on the expected use of the papermaking belt. When the papermaking belt 10 is to be used in the papermaking process 10 described below, it is preferred that the thickness t of the papermaking belt 10 be about 0.01 to 3.0 mm. Other applications may, of course, require thicker papermaking belts, which may be 3 cm or more thick.

Any suitable means for adjusting the thickness 15 may be used. The illuminated means for adjusting the thickness of the overload in Fig. 22 is to use a leaving roller 81, which also acts as a mask guide roller. The distance between the leaving roller 81 and the forming unit 71 can be adjusted mechanically by any conventional means not shown. In connection with the mask 74 and the mask guide roller 82, the leaving roller 81 tends to smooth the surface of the liquid photosensitive resin 70 and adjust its thickness.

Sixth Step The sixth step of the method of the present invention can be considered as either a single step or two consecutive steps comprising (1) providing a mask 74 having opaque areas 74a and transparent areas 74b, wherein the opaque areas 74a together with the transparent areas 74b define and (2) placing a mask 74 between the liquid photosensitive resin coating 70 and the actinic light source 73 such that the mask 74 is in contact with the first surface 34 'of the liquid photosensitive resin coating 70.

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Alternatively, the mask 74 may be positioned so as to be spaced a certain distance from the first surface 34 'of the coating 70. However, for the reasons described below, it is preferably in contact with the first surface 34 'of the coating 70.

The purpose of the mask 74 is to protect, i.e., shield, certain areas of the liquid photosensitive resin 70 from exposure to light from an actinic light source. If certain areas are shaded, the natural consequence is that certain areas are not shaded and the liquid light-sensitive resin 70 in said unshaded areas is subsequently exposed to activating light and cures. When the steps described herein are performed, the shaded areas comprise a normal preselected pattern formed by channels 36 in the cured resin lattice 32.

The mask 74 may be made of any suitable material that may be provided with opaque areas 74a and transparent areas 74b. The flexible film-like film material is suitable for use as a mask 74. The flexible film may be polyester, polyethylene, or cellulosic or other suitable material. The opaque regions 74b should be opaque to the curing light of the photosensitive liquid resin. In the case of the preferred liquid photosensitive used herein, the opaque regions 74a should be opaque to light having a wavelength of about 200 to 400 nm. The opaque areas 74a can be provided to the mask 74 by any suitable means, such as blue copying (i.e., azalide methods) or photographic, gravure, flexographic, or rotary screen printing methods. The opaque areas 74b are preferably provided to the mask by the blueprint method (i.e., the frontalide method).

li 97552 97

The mask 74 may be an endless loop (details of which are conventional and therefore not shown) or it may be fed from the feed roll transversely through the system to the take-up roll, neither of which is shown in the figure, as they are also conventional. The mask 74 travels in the direction indicated by directional arrow D3, turns under nip roll 81 where it is brought into contact with the liquid va lonherkän surface of the resin 70, and then passes the mas kinohjaustelalle 82 in the vicinity of 10 is removed from contact with the resin 70. In this particular embodiment, the thickness adjustment of the resin 70 and the placement of the mask 74 occur simultaneously.

Seventh Step The seventh step 15 of the method of the present invention comprises curing a liquid photosensitive resin coating in areas left unshaded by transparent areas 74b of the mask 74, and curing portions of the coating 70 that are cured by the second portion Ρθ2 of the reinforcing structure 33 and shaded portions. the first part P01 of the reinforcing structure 33 and the forming. not curing the coating portions interposed between the work surface 72 of the unit 71 by exposing the liquid photosensitive resin coating with light 70 from the light source 73 having an activating wavelength through a mask 74 25 to form a partially formed composite belt 10 '.

In the illustrated embodiment of Figure 25, the barrier film 76, the reinforcing structure 33, the liquid photosensitive resin 70, and the mask all form a unit that runs as a whole from the discharge roll 81 to the vicinity of the mask guide roll 82. Between the leaving roll 81 and the mask guide roll 82, and at the point where the barrier film 76 and the reinforcing structure 33 are still against the forming unit 71, the liquid photosensitive resin 70 is treated with light having an activating wavelength of 35 and supplied from an exposure lamp 73.

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The exposure lamp 73 is generally selected to provide illumination that is substantially in the wavelength range causing the liquid photosensitive resin 70 to cure. This wavelength is one of the characteristic properties of liquid-5 of its photosensitive resin 70. Any suitable light source, such as mercury arc, pulse xenon, electrodeless and fluorescent lamps, can be used. As described above, upon treatment of a liquid photosensitive resin with light having a suitable wavelength, curing is initiated in the exposed areas of the resin 70. Curing usually manifests as solidification of the resin in exposed areas. Unexposed areas, on the other hand, remain fluid.

The intensity of the exposure and its duration depend on the degree of curing required in the exposed areas. The absolute values of the exposure intensity and time depend on the chemical nature of the resin, its light properties, the thickness of the resin coating and the pattern chosen. For the preferred resin, Merigraph EPD 1616, this amount is in the range of about 100 to 1,000 mJ / cm 2, with the preferred range being about 300 to 800 mJ / cm 2 and the most preferred range being about 500 to 800 mJ / cm 2.

The exposure intensity and the angle of incidence of light have an important effect on the presence or absence of gradient 25 in the walls 44 of the channels 36. In addition to the effect of exposure intensity and angle of incidence on the walls 44 of channels 36, they affect the air permeability of the cured lattice 32. Air permeability ("air permeability") is important for the use of the papermaking belt 30 of this invention in papermaking processes in which blow drying is performed. It will be appreciated that if the degree of collimation of the activating light of the wavelength is high, the walls 44 of the channels 36 will be less inclined. Less sloping (i.e., closer to the vertical) duct walls give the papermaking belt

II

. 97552 99 higher air permeability than inwardly sloping walls (with the knee area of the first surface being determined) because the total area of the papermaking belt through which air can flow is larger when the walls 44 of the chickens 36 are not inwardly sloping.

In a preferred embodiment of the present invention, the angle of incidence of light is collimated to cure the photosensitive resin in better desired areas and to provide a desired angle of inclination in the walls 44 of the finished papermaking belt 10. Other means of controlling the direction and intensity of curing radiation include folding means. reflective devices (i.e. mirrors). In a preferred embodiment of the present invention, a subtractive collimator 15 (i.e., an angle distribution filter or a collimator that filters or blocks UV light rays in non-desired directions) is used. Any suitable device can be used as the subtractive collimator. A dark, preferably black, metal device shaped as a series of 20 channels through which light directed in a desired direction can pass is preferred. In a preferred embodiment of the present invention, the collimator is dimensioned to transmit light such that the projection of the surface of the cured resin network is 35% above the papermaking belt and 65% behind.

The eighth step

The eighth step in the method of the present invention is the removal of substantially all of the uncured liquid photosensitive resin from the partially formed composite belt 10 ', leaving the cured resin grid 32 around at least a portion of the reinforcing structure 33.

At this point, the light-shielded resin is removed from the partially formed composite belt 10 '10 as described below to provide a lattice 97552 100 32 with a plurality of channels 36 in areas shaded by opaque areas 74a of the mask 74 from light rays and passageways 37 forming a surface texture. , the framework 32 to the backside network of 5-nervous 35a of the points where the second surface of the coating 35 'has penetrated into the forming unit 71. The texture of the working surface 72.

In the embodiment shown in Figure 25, at a location near the mask guide roller 82, the mask 74 and barrier film 76 are physically separated from a partially formed composite belt 10 'comprising a reinforcing structure 33 and now a partially cured resin 70 and a certain amount of uncured resin. The composite formed by the reinforcing structure 33 and the partially cured resin 70 passes to the area 15 of the first resin removal shoe 83a. A vacuum is applied to the second surface of the composite belt 10 'at the first resin removal shoe 83a so that a substantial amount of uncured liquid photosensitive resin exits the composite belt 10'.

As it advances, the composite belt 10 'enters the resin wash jet 84 and the resin wash station drain 85, where the composite belt 10' is thoroughly washed with water or other suitable liquid to remove substantially all of the remaining uncured liquid photosensitive resin 85 from the resin 25 system. At the second resin removal shoe 83b, any remaining washing liquid and uncured liquid resin are removed from the composite belt 10 'using a vacuum. At this point, the composite belt 10 'comprises a reinforcing structure 33 and an associated cured resin lattice 32 and represents the papermaking belt 10 which is the product of this method.

As shown in Fig. 25, a second treatment of the resin with activating light (hereinafter sometimes referred to as the "post-curing step") may optionally, and preferably, be performed to complete the curing of the resin and to improve the hardness and durability of the cured resin lattice 32. The post-curing step occurs at the location indicated by reference to the following Figure 26. Figure 26 is an enlarged schematic representation of this post-curing step.

As shown in Fig. 26, the composite belt 10 'is exposed a second time with light having an activating wavelength using a post-curing UV light source 73a. However, this second exposure occurs when the composite belt 10 'is submerged under water 86. To immerse the composite belt 10 ', the composite belt 10' is deflected somewhat from the path it has traveled by rollers 87a, 87b, 87c and 87d in the water 86 of the water bath 88, as shown in Figure 26. It has been found important to be immersed in this post-curing exposure; the finished strap 10 is otherwise too sticky or sticky. In addition, it has been found necessary to add sodium sulfite (NA 2 SO 3) to remove dissolved oxygen from the water 20 as much as possible to facilitate complete polymerization of the resin. Sodium sulfite is added to up to about 2% by weight of the water in the post-curing bath 88.

Fig. 26 further shows that in this post-curing, a mirror 89 is placed on the bottom surface 25 90 of the water bath 88. The function of the mirror is to reflect the UV light coming to the mirror 89 back below the composite belt 10 ', i.e. the backing side 12. This step is especially important to completely cure its resin portion. forming a second surface 32 of the passageways and irregularities in the finished papermaking belt 35 of the framework October 30 in the backside network 35a. As shown in the previous figure, all UV light is supplied from sources located above the top surface of the composite belt 10 '. In this case too, the amount of UV light supplied during this post-curing depends on the resin in question as well as on the desired depth and pattern of curing. In the case of the preferred resin, Merigraph resin EPD 1616, the dosages defined above in connection with the pre-curing step are also suitable for the post-curing step. However, it is not necessary to collimate the light in the post-curing step, since the channels are already suitably formed in the lattice.

The process is continued until the reinforcing structure 33 has been machined along its entire length and converted into a papermaking belt 10.

10 If it is desired to form a papermaking belt having different patterns superimposed or patterns of different thicknesses, the reinforcing structure may be passed through the process several times. Several exports through the process of this invention can also be used to form relatively thick papermaking belts.

3. Papermaking method

The following describes a papermaking process utilizing the improved papermaking belt 10 of the present invention, although it is contemplated that other methods may be used to make the paper products described herein. As a background, a method of making paper that does not incorporate the improvements provided by this method and does not use the improved papermaking belt 10, 25 of the present invention is described in detail in U.S. Patent 4,529,480 (Tissue Paper, Paul, D. Trokhan, July 16, 1985). . The Trokhan patent is incorporated herein by reference to the extent that it is consistent with this description. The following are improvements to the method described in the Trokhan patent.

The overall papermaking process using the papermaking belt of the present invention comprises a series of steps or operations that generally occur in the chronological order set forth below. In the following chapters, each step is discussed in detail with reference to Figure 1. However, it is to be understood that the steps described below are intended to assist the reader in understanding the method of the present invention and are not limited to methods having only a predetermined number of steps or arrangements. In this respect, it is noted that it is possible to combine the following steps so that they are carried out simultaneously. It is also possible to divide the following steps into two or more steps without departing from the scope of the present invention.

Figure 1 is a simplified schematic representation of one embodiment of a continuous paper machine useful in carrying out the papermaking process of the present invention in practice. The papermaking belt 10 of the present invention is shown in the form of an endless belt. The specific paper machine illustrated in Figure 1 is a flat wire machine having a structure and belt arrangement to the East generally similar to the paper machine disclosed in U.S. Patent 3,301,746,20 (Sanford and Sisson, January 31, 1967), which is incorporated herein by reference.

It is also contemplated that a twin wire paper machine illustrated in Figure 1 of U.S. Patent 4,102,737 (Morton, July 25, 1978), which is incorporated herein by reference, could be used to practice the present invention. If the twin wire paper machine disclosed in U.S. Patent No. 4,102,737 (Morton) is used to practice the present invention, the papermaking belt of the present invention would replace the drying-heel press fabric represented by No. 4 in the drawings of the Morton patent. However, all other references to the drawings refer to the drawings appended to this specification.

- 97552 104

First phase

The first step in carrying out the papermaking process of this invention is to provide an aqueous dispersion 14 of paper fibers.

An apparatus for preparing an aqueous dispersion 14 of paper fibers is well known and is therefore not shown in Figure 1. The aqueous dispersion 14 of paper fibers is placed in a headbox 13. Figure 1 shows one headbox. However, it is to be understood that there may be multiple headboxes in alternative arrangements of the papermaking process of the present invention. The headbox or headboxes and apparatus for preparing an aqueous dispersion of paper fibers are preferably of the type disclosed in U.S. Patent 3,994,771 (Morgan and Rich, November 30, 1976), which is incorporated herein by reference. The preparation of the aqueous dispersion and the characteristic properties of the aqueous dispersion are described in more detail in U.S. Patent 4,529,480 (Trokhan, July 16, 1985), which is incorporated herein by reference.

The paper fiber aqueous slurry 14 fed from the headbox 13 is applied to a forming belt, such as a flat wire 15, to carry out the second stage of the papermaking process. The flat wire 15 is supported by a chest roll 16 and a set of return rolls, denoted by the numbers 17 and 17a. Tasovii-25 RAA 15 is rotated in the arrow A direction indicated by a conventional drive means which is not shown in Figure 1. The paper machine shown in Figure 1 may also be associated auxiliary units and devices which are commonly associated with paper making machines and linear screens, including rintapöy-30 DAT, hydrofoils, vacuum boxes, tension rollers, support rollers, wire cleaning jets, etc., which are conventional and are therefore omitted from Figure 1.

Second step

The second step of the papermaking process is to form a paper-35 fibrous primary web 18 on the porous surface 97552 105 from the aqueous dispersion 14 fed in the first step. The Ta 15 wire acts as a porous surface in the paper machine shown in FIG. As used herein, “elemental web M” is a fibrous web that is rearranged by the papermaking belt of the present invention during the papermaking process.

The characteristics of the primary web 18 and various possible methods for forming the primary web 18 are described in U.S. Patent 4,529,480, which is incorporated herein by reference. In the process shown in Figure 1, the elementary web 18 is formed from an aqueous dispersion 14 of paper fibers between a breast roll 16 and a return roll 17 by depositing an aqueous dispersion 14 on a flat wire 15 and removing a portion of the aqueous dispersing medium. Conventional suction boxes, chests, discharge strips, etc., not shown in Figure 1, are useful for removing water from the aqueous dispersion 14.

Once the elementary web 18 is formed, it travels with the planar wire 15 around the return roll 17 and is brought into the vicinity of the papermaking belt 10, the papermaking belt 10 of the present invention.

The third stage

The third stage of the papermaking process, the embryonic web 18 is contacting (or associating) with 25 in contact with the papermaking belt of the present invention 10 in the paper side 11.

The purpose of this third step is to bring the contact 18 into contact with the embryonic web with a papermaking belt 10 of the paper side, for which the Al-30 keisrainalle 18 and the individual fibers therein are then deflected, rearranged, and further water removal. The elementary web 18 is brought into contact with the papermaking belt 10 of the present invention by means of a flat wire 15. The planar wire 15 contacts the elementary web 18 with the papermaking belt 10 97552 106 of the present invention and transfers the elementary web 18 to this belt at the vacuum catch 24a.

shown in Figure 1, the papermaking belt of the present invention 10 passes arrow B direction indicated by 5. The papermaking belt 10 ribs the papermaking belt return rollers 19a and 19b, the printing roll 20, the papermaking belt return rollers 19c, 19d, 19e and 19f, and the emulsion application roller 21 (which applies the emulsion 22 to the papermaking belt 10 from the emulsion bath 23). The loop rotated by the papermaking belt 10 of the present invention also includes means for applying a liquid pressure difference to the paper web, comprising, in a preferred embodiment of the present invention, a vacuum catch 24a and a suction box such as a multi-slot suction box 15 24. There is also a pre-dryer 26 along the circuit. 19d and also between the papermaking belt return rollers 19d and 19e are further water jets 102 and 102a, respectively. The purpose of the water jets 102 and 102a is to clean the papermaking belt 10 20 of any papermaking fibers, adhesives, etc. that are trapped in the portion of the papermaking belt 10 that has passed through the final stage of the papermaking process. The papermaking belt 10 of the present invention, as well as those omitted from Figure 1, includes additional support rollers, return rollers, cleaning means, actuators, etc., which are commonly used in paper machines and are well known to those skilled in the art.

The operation of the emulsion application roller 21 and the emulsion bath 23 is discussed in connection with the third step for reasons of expediency. The emulsion application roller 21 and the emulsion bath 23 continuously apply an effective amount of chemical compounds (or compounds) to the belt 10 during the papermaking process. The chemical compounds can be applied to the papermaking belt 10 at any stage during the papermaking process 35, although it is preferred to add 97552 107 chemicals to the paper contacting side 11 of the belt 10 at a point in the belt cycle where the belt 10 does not support the paper web. This normally occurs (as described in more detail below) after the pre-dried paper web 27 has been transferred from the papermaking belt 10 to the surface of the Yankee cylinder 28 and the belt 10 is returning to contact with the second elementary web 18 (i.e. at the emulsion application roll 21).

One or more chemical compounds are applied to the papermaking belt 10, preferably in the form of an emulsion, such as the emulsion 22 shown in Figure 1. These one or more compounds have the following two functions: (1) to act as a release agent or release emulsion (with a papermaking belt according to the present invention); detaches from the belt and does not stick to it once the steps of the papermaking process have been carried out on the paper web); (2) treating the belt to extend its service life by reducing the resilience of the resin lattice 32 to decompose due to oxidation (i.e., the emulsion 22 also acts as an antioxidant). One or more chemical compounds are preferably applied uniformly to the paper-contacting side 11 of the belt 10 so that the paper-contacting side 11 benefits substantially the entire area from the chemical treatment.

The preferred emulsion 22 consists essentially of five compounds, although it is contemplated that suitable substitutes or additional compounds could be used. The preferred composition contains water, a high power turbine oil known as "Regal Oil", dimethyl distearyl ammonium chloride, cetyl alcohol and an antioxidant.

As used herein, the term "Regal Oil" means a blend containing about 87% saturated hydrocarbons and about 12.6% aromatic hydrocarbons and very small amounts of additives, manufactured by Texaco Oil Company, 35 Houston, Texas, under part number R & 0 68 Code 702. Regal 97552 108

The purpose of the oil in the composition described above is to provide an emulsion having properties that allow it to act as a release agent.

Dimethyl distearyl ammonium chloride is sold by Sherex 5 Chemical Company, Inc., Rolling Meadows, Illinois, under the tradename ADOGEN TA 100. Hereinafter, dimethyl distearyl ammonium chloride is referred to as ADOGEN for convenience. ADOGEN is used in an emulsion to emulsify or stabilize oil particles of a surfactant (Regal Oil) in water. As used herein, the term "surfactant" means a surfactant having one end hydrophilic and the other end hydrophobic and extending at the boundary between the hydrophilic agent and the hydrophobic agent to stabilize the two agents.

15 As used herein, "cetyl alcohol" means a linear C16 fatty alcohol. Cetyl alcohol is manufactured by The Procter & Gamble Company, Cincinnati, Ohio. Like ADOGEN, acetyl alcohol is used as a surfactant in the emulsion used in this invention.

20 As used herein, the term "antioxidant" refers to a compound that, when applied to an oxidized surface of an article, reduces the tendency of the article to oxidize (i.e., coalesce with oxygen). In particular, in this specification, the term "antioxidant" means compounds that reduce the tendency of the cured resin network of the papermaking belt 10 of the present invention to oxidize. One preferred antioxidant is Cyanox 1790 sold by American Cyanamid, Wayne, New Jersey 07470.

The relative proportions of the compounds used in the emulsion are shown in the following table: 97552 109

Component Volume (1) Weight (kg)

Water 1 961 1959.51

Regal Oil 208 190.96 ADOGEN N / A * 10.9 5 Cetyl alcohol N / A * 7.3

Cyanox 1790 N / A * 2.63 N / A * - The component is added in solid form.

Fourth Step 10 In the fourth step of the papermaking process, the liquid pressure difference of the suitable fluid is directed to the primary web 18 by a vacuum source to direct at least a portion of the primary web 18 paper fibers to the papermaking belt 10 channels 36 is also to rearrange the fibers in the elementary web 18 into the desired structure.

The preferred method of achieving the fluid pressure difference, as also described more fully herein, is al-. positioning the caustic web 18 in such a way that the web is subjected to a vacuum through the channels 36 by directing the vacuum from the back side 12 of the papermaking belt 10 of the present invention. In Figure 1, this preferred method is illustrated by the use of a vacuum trap 24a and a multi-slit suction box 24. Preferably, a suction pressure of about 27.09 to 40.64 kPa is used in the vacuum trap 24a and a suction pressure of about 50.8 to 67.7 kPa in the multi-slit suction box 24. Thus, in a preferred embodiment of the method of the invention, the liquid pressure difference is typically a negative pressure (i.e., below normal pressure) and the suitable fluid is air. Alternatively or in addition, a positive pressure in the form of air or water vapor pressure can be directed through the planar wire 15 to the elementary web 18 at the catcher 35a or the suction box 24. Means for directing such a positive pressure are conventional and are therefore not shown in Figure 1.

Figures 1A and 1B illustrate the guide of fibers to the channels 36. Figure 1A is a simplified cross-sectional view of a portion of the papermaking belt 10 and the primary web 18 when the primary web 18 is introduced into the papermaking belt 10 but before the fibers are directed to the channels 36. As shown in Figure 1A, the primary web 18 is further in contact with the flat wire 15 (or more specifically between the flat wire 15 and the papermaking belt 10 of the present invention). Figure IA shows only one channel 36 and the embryonic web 18 is shown associated with the papermaking belt 10 of the framework 32 of the paper side network of a top-to 34a.

The portion of the papermaking belt shown in Figures 1A and 1B is simplified by omitting the reinforcing structure generally part of the preferred embodiment of the papermaking belt of the present invention, and also showing the walls of the channels 36 in straight vertical lines 20 in a cross-sectional view when the profile of the channels 44 in the preferred embodiment described above. is somewhat more complex. In addition, the opening 36 of the channel 36 in the first surface 34, the first channel opening 42, and the opening 25 in its second surface 35, the second channel opening 43, are shown to be approximately the same size and shape as in the preferred embodiment of the present invention. the openings are smaller than the channel openings in the first surface 34.

Fig. 1B is a simplified cross-sectional view of a portion of the papermaking belt 10, similar to Fig. 1A. Figure IB shows that 35 integral part of the embryonic web 18 of fibers, and thus self-97 552 111 from the embryonic web 18 is transferred to the channel 36 of the paper side network surface beneath 34a to form välituo-Teraina 25, the embryonic web 18 individual fibers rearrangement (the details of which are not shown) with event-5 Come during steering.

Figure 1B also shows that in the step where the fibers in the base web 18 are guided into the channel 36 and rearranged, the base web 18 is no longer in contact with the flat wire 15. As shown in Figure 1, the web 18 is separated from the flat wire 15 immediately after leaving the catch 24a.

Either at the time the fibers are directed to the channels 36, or after such guidance, water is removed from the primary web 18 through the channels 36. Dewatering takes place due to the pressure difference of the liquid-15. It is important, however, that an essential part of water removal from the embryonic web does not occur before guiding the fiber channels 36. As an aid in achieving this condition is that at least the paper side network 34a surrounded by channels 36, are generally isolated as a 20-tyjä each other. This isolation, or partitioning, of the channels 36 is important to ensure that the guiding force, such as the vacuum, is directed relatively abruptly and is used to a sufficient extent to guide the fibers. This should be compared to the state-25 tea where the channels 36 are not insulated. In this latter situation, the vacuum penetrates the adjacent channels 36, resulting in a gradual effect of the vacuum and removal of water without associated fiber deflection.

In the machine illustrated in Figure 1, dewatering takes place initially at the catch 24a and the suction box 24. Because the channels 36 are open through the papermaking belt in its thickness direction, the water exiting the primary web 18 passes through the channels 36 and out of the system. Dewatering leaves 97552 112 months until the consistency of the web associated with the channels 36 increases to approximately 20-35%.

The fifth step

The fifth step is the conveying of the papermaking belt 10 and the al-5 core web 18 over the vacuum source described in the fourth step. The fifth step is preferably carried out when the fourth step takes place. The belt 10 conveys the elementary web on its side in contact with the paper 11 over the vacuum source. At least a portion of the textured 10 backside 12 of the belt 10 is generally in contact with the surface of the vacuum source as the belt 10 passes over the vacuum source.

The step of the papermaking belt 10 of the present invention passing over a vacuum source reduces the undesired accumulation of paper fibers at the edges of the suction box. Without wishing to be bound by any particular theory, it is believed that one of the critical factors in achieving this reduction in the method of the present invention is the control of the relative abruptness of steering during the preceding step. Deflection of the fibers in regulating-20 to L using the papermaking belt having a texture-buffered backside 12. The textured backside surface allows air into a certain amount of flow into the papermaking belt 10. The backside 12 across the backside 12 is in contact with the pickup shoe 124a and the suction box 24 surfaces with 25 SA. The belt 10 in the backside network 35a is the passageways 37 that provide a space through which at least a portion of this air can flow in. This has to be compared to the previous steering part, which was equipped with a relatively flat bottom surface. The flat surface tended to form a barrier to the suction box used to guide the fibers of the primary web, resulting in an extremely sudden effect of the suction pressure when the barrier opened. Thus, the control of the deflection of the fibers of the elementary web 18 may be a step that occurs naturally in connection with the fifth step, or may be considered a separate step.

97552 113

It is also assumed that these passageways 37, which form surface texture irregularities 38 on the back side 38 of the papermaking belt 10, have the effect of cleaning the edges or surfaces of the vacuum dewatering apparatus 5 used in the papermaking process. This cleaning operation tends to eliminate any undesirable accumulation of paper fibers on this vacuum equipment. This cleaning effect is assumed to occur when the vacuum source has at least one surface over which the papermaking belt 10 passes during the control step. Thus, the cleaning of the surfaces of the vacuum dewatering equipment may be a step that occurs naturally in connection with the fifth step, or it may be considered as a separate step. If this step is considered as an additional step, this would involve removing any accumulated on the surface of said vacuum source with said 15 contacting the surface of the belt 10 of the textured backside 12 of paper fibers on the vacuum source.

After suction pressure has been applied and the papermaking belt 20 and the primary web 18 have passed over the vacuum source, the primary web 18 is in a state where it has been subjected to a differential pressure and directed but has not been completely dewatered, so it is now referred to as an "intermediate web 25". .

25 The sixth step

The sixth step of the papermaking process is an optional step comprising drying the intermediate web 25 to form a pre-dried paper fiber web. Any suitable method traditionally known in the papermaking industry can be used to dry the intermediate web 25. For example, flow-through dryers, heat-free capillary dewaterers, and Yankee cylinder dryers alone and in combination are satisfactory.

97552 114

Figure 1 illustrates one preferred method for drying the intermediate web 25. After leaving vacuum box 24, although associated with the papermaking belt 10 of the intermediate web 25 passes around the papermaking belt return roll 19a and travels in 5 the direction of arrow B indicating the direction. The intermediate web 25 then passes through a possible pre-dryer 26. This pre-dryer 26 may be a conventional flow-through dryer (hot air dryer) well known to those skilled in the art.

The amount of water leaving the pre-dryer 26 is controlled so that the consistency of the pre-dried web 27 leaving the pre-dryer 26 is about 30-98%. The pre-dried web 27, which is still associated with the papermaking belt 10, passes around the return roll 19b of the papermaking belt and passes into the area of the printing waste roll 20.

15 The seventh step

seventh step in the papermaking process is the 10 paper side network of the papermaking belt of the present invention, pressing the predried web 34a by placing the predried web 27 between the papermaking belt of the printing surface 10 and 20, to form an embossed pa-charged fibrous web.

If a possible sixth pre-drying step has not been performed on the intermediate web 25, this seventh step is performed on the intermediate web 25.

The seventh step is carried out in the machine illustrated in Figure 1 as the pre-dried web 27 passes through a gap formed between the printing waste roll 20 and the Yankee cylinder 28. When the predried web 27 passes through this nip, ver-network pattern by the paper side network 34a formed with the PA-30 papermaking belt 10. The paper side 11 of the contact, is pressed predried web 27 to form the embossed web 29.

The eighth step

The eighth step of the papermaking process is the drying of the heel-35 pressed web 29. Embossed web 29 - 97 552 115 differs from the papermaking belt 10 of the present invention after the paper side network 34a is printed on the web 29 to form the earring-kopuristetun web. When the heel press web 29 differs from the papermaking belt 10 of the present invention, it adheres to the surface of the Yankee cylinder 28 to dry it to a consistency of at least about 95%.

The portion of the web 10 carrying the web passes around the return rollers 19c, 19d, 19e and 19f of the papermaking belt 10 and the jets 102 and 102a interposed therebetween, where it is cleaned. From the jets, a portion of this belt passes to an emulsion roll 21 where it receives a new dose of emulsion 22 before coming into contact with the second portion of the elementary web 18.

15 The ninth step

The ninth step in the papermaking process is to shorten the dried web (heel-pressed web 29). This ninth step is a possible, but very preferred, step.

As used herein, shortening refers to a reduction in the length of a dry paper web that occurs when energy is directed to the dry web in such a way that the length of the web decreases and the fibers in the web rearrange, resulting in rupture of the bonds between the fibers. The shortening can be done in any of a few well-known ways. The most common and preferred method is creping.

In the creping operation, the dried web 29 is attached to the surface and then removed from this surface by a scraper 30a 30. As shown in Fig. 1, the surface to which the web is usually attached also acts as a drying surface. This surface is typically the surface of a Yankee cylinder 28, as shown in Figure 1.

The adhesion of the heel-pressed web 29 to the surface of the Yankee-35 cylinder 28 is facilitated by the use of a creping joint. Typical creping adhesives may include any suitable adhesives, such as polyvinyl alcohol based adhesives. Specific examples of suitable adhesives are described in U.S. Patent 3,926,716 (Bates, December 16, 1975), which is incorporated herein by reference. The adhesive is applied either to the pre-dried web 27 immediately before it passes through the roll gap described above, or more preferably to the surface of the Yankee cylinder 28 before the web is pressed against the surface of the Yankee cylinder 28 by the weight leaving roller 20.

The adhesive application means and the method for applying the adhesive used in the practice of the present invention are conventional and are therefore not shown in Fig. 1. Any method known to those skilled in the art for applying creping adhesives, such as spraying, can be used.

15 In general, only 29 channels ohjautumattomat parts of the web that have been linked with the papermaking belt 10 of the paper-contacting side 11 of the paper-side network 34, 28 is glued directly to the surface of the Yankee cylinder. The paper side network 34a of the pattern and the Ori-20 mutation in relation to the scraper 30 is determined to a large extent RAI wholly amount and nature of the creping to occur.

The physical characteristics of the paper web 31 produced by the process of this invention are described in the aforementioned U.S. Patent 4,529,480 25 ("Tissue Paper", Trokhan, July 16, 1985), which is incorporated herein by reference. However, the web area of the paper web and the plurality of domes conform to the "linear Idaho pattern" instead of the hexagonal pattern shown in the drawings of U.S. Patent 4,529,480 due to the different shape of the channels in the preferred embodiment of the papermaking belt 10 of the present invention.

The paper web 31, which is a product of the present invention, may optionally be calendered and either rewound with or without differential winding or cut and stacked, all operations 97552 117 being performed by conventional means not shown in Figure 1. The paper web 31 is then ready for use.

4. Test methods

It has been found that belts with a certain amount of 5 backside texture will achieve the desired goals, the paper fibers in the vacuum dewatering an undesirable reduction in surface deposition and controlling the other problems associated with the fiber accumulation. Background The amount and character, which must be present in order to achieve the desired 10 using the results of the papermaking belt 10 of the present invention, it is a feature of the belt, which is called a belt, or more specifically from 12 läpikulkukapasiteetiksi fluids of the belt backside textured surface, the text-turoinnin. As used herein, the term "fluid throughput" means the amount of air (i.e., "air leakage") passing across the back surface 12 of the papermaking belt 10 under the conditions of the test developed for this specific purpose described below.

Air leakage across the back surface 20 12 of the papermaking belt 10 is hereinafter sometimes referred to as "XY plane" air leakage. The term "XY" is derived from the fact that if the papermaking belt 10 of the present invention were placed in a rectangular coordinate system so that the back side 12 of the papermaking belt 10 and in the plane formed by the y-axes, the air leak of interest would be a leak that occurs along the back side 12 of the belt 10 in any direction in the XY plane.

X-Y or backside air leakage test utilizes a device which is represented schematically in Figures 30 to 30 and 31. Figure 30 shows a schematic plan view of the backside leakage testing device 56 of the upper surface. All hoses and pipes generally associated with the test apparatus are omitted from Figure 30 for simplicity. These hoses and tubes are best seen in the side view of the device shown in Figure 31. As these 97552 118 shown in the figures, the backside leakage testing device 56 has as its basic components, a stand 57, which includes a first plate 58 having a central opening 59; a smooth circular second plate detached from the rack, which can be placed on the opening 59 in the first plate 58; a liquid-filled vacuum meter 62 and a flow meter 63.

The plate forming the top of the rack (i.e., the first plate 58) is in its preferred shape a square having dimensions of 20.32 cm x 20.32 cm and a thickness of 1.27 cm. The first plate 58 provides a smooth, deformable, and impermeable to fluids (i.e., gases and liquids) surface. It is preferably made of stainless steel with a mirror-bright wedge-15 and extremely smooth surface. For accurate readings, it is especially important that there are no scratches or other defects on the surface of this disc. Such surface defects allow for additional air leakage, resulting in higher readings than would be obtained if the first plate 20 58 did not have such defects. The diameter of the hole in the center of this disc is 2.54 cm. In addition, the rack used for the test described herein has a circle engraved on the first plate 58 with a diameter of about 8.89 cm and centered around the opening 59. The purpose of this circle is to act as a guide for centering the second plate 60 over the opening 59. This circle is not expected to affect the accuracy of the readings.

The circular second plate 60, which is not part of the rack, is also made of stainless steel in its preferred form and has a diameter of 7.62 cm and a thickness of 1.27 cm. The mass of the second plate 60 is 405 g. The mass must be sufficient to hold the belt sample to be tested on the rack without compressing it unnecessarily.

As shown in Figure 31, the adapter 61 fits inside the opening 59 in the first plate 58 in such a way that a pipe or hose can be placed in the opening 59 and held in place therein. The adapter 61 has a short tube 64 extended at least at one end. This tube 64 extends towards the mouth of the opening 59 on the surface of the first plate 58 on which the part of the belt to be tested rests. The inner diameter of the tube 64 from the fitting 16 is 0.793 cm.

At one end of the adapter 61, a hose 65a runs to the bottom of the flow meter 63. A flow meter 63 is used to measure the air flow rate through the test portion of the papermaking belt 10. The flowmeter has a numerical scale from 0 to 150. As with most flowmeters, no specific units are marked on the scale. Therefore, the flow meter 63 is calibrated with respect to a known unit, as described in more detail below. One suitable flowmeter is a meter labeled FM 102-05 manufactured by Cole Parmer Company, Chicago, IL 60648.

Another hose 65b runs from the top of the flow meter 63 to a tube 68 which is ultimately connected to a vacuum source 20 which draws a vacuum in the direction of the arrow VT. The vacuum source itself. de is conventional and is therefore not shown in Figure 33. The tube 68 running from the hose 65b to the vacuum source has a few branches. These branches have a shut-off valve 69a, a coarse control valve 69b and a fine control valve 69c 25, as well as a liquid-filled vacuum gauge 62 calibrated for a pressure range of 0 to 762 mmHg. Any meter that accurately measures vacuum in millimeters of mercury is suitable. One example of such a vacuum gauge is a model designated AISI 316 Tube & socket 30 No. 250.2274A manufactured under the tradename Ashcroft Dura-gauge, Stratford, CT.

In use, a piece of papermaking belt 10 is placed over an opening 59 in the plate 58 of the X-Y leak test rack 57. A piece of papermaking belt 10 is placed on the plate with the side 11 in contact with the paper-35 facing upwards (i.e.

97552 120 away from the plate 58) and the back side 12 directly onto the plate 58. The piece taken from the papermaking belt 10 should be of sufficient size to be at least larger than the circular second plate 69 in all directions. However, Figures 32 and 33 5 show only a portion of the papermaking belt piece 10 to illustrate the point. In addition, it should also be noted that the part of the papermaking belt 10 shown in these figures is greatly exaggerated due to the illumination with respect to the size of the leak test apparatus 56.

10 The second plate 60 is then placed with the papermaking belt 10 of the paper-contacting side 11 over to hold the belt in place and the test Pape rinvalmistushihnapalan 10 for covering the channels 36 to prevent the air to come through the channels 36. Suction pressure is applied to the sample and valves 69a, 69b and 69c are adjusted so that the preset value of the pressure difference measured by the vacuum gauge 62 is about 177.8 mmHg. However, the readings have been taken with a preset value of 127 mmHg displayed by the vacuum gauge 62 before the fully standardized procedure is established. Readings taken at 127 mmHg can be converted to readings taken at 177.8 mmHg by fitting the readings taken at 127 mmHg to the following equation, where x is the reading taken at 127 mmHg and y is the corresponding reading at 177 mmHg: 25 y = 2.6720 + l, 2361x

When the sample is thus directed to the suction pressure, into a direct reading of flow meter 63. The flow meter 30 63 directly read a measure of the XY plane discharge portion 10 of papermaking belt backside 12 of the cross and, more particularly defined in the second plate 60 around the periphery (as indicated by arrows L direction) finish and tested paper-manufacturing belt 10 backside 12 of the cross-flowing air 35 vol. This unit of reading has been given the name 97552 121 si "marlatt" according to Henry Marlatt, Mehoopany, Pennsylvania, who is the person responsible for taking some air leak readings using the test described above. Marlats can be converted to standard cubic centimeters per 5 minutes by fitting the reading measured in marlats to the following equation, where x is the reading in marlates and y is the corresponding value in standard cubic centimeters per minute: y = 36.085 + 52.583x - 0.07685x2.

10 This equation for converting marlats to standard cubic centimeters per minute was developed by calibrating the flow meter to cm3 / min (NTP) using a Buck Optical Soap Bubble Meter. The relationship between the readings taken directly in marathes by the flow meter 15 and the corresponding standard cubic centimeter / min reading is shown graphically in Figure 32.

The flow capacity of the fluids (i.e., the amount of air leakage measured by the test described above) should not be less than about 35 marlats [about 1,800 cm 3 / min (NTP)]. Belts with a fluid throughput of 35 marlats are beginning to achieve some of the benefits of reducing the accumulation of paper fibers in the vacuum water-25 removal equipment used in the papermaking process. In other words, the 32 second surface of the grid of the passageways 37 should be together with form elements of the backside texture of a size or capacity sufficient päästääkeen of at least about 1 800 cm 3 / min (NTP) of air or other fluid-30 agent in a pass (i.e., escape) of the belt textured backside surface across when the back side 12 of the belt 10 is brought into contact with a smooth, deformable, liquid impermeable surface and the channels 36 are covered so as to prevent air or fluid from coiling through the channels 36, and a liquid pressure difference is applied to the back side of the belt 10 - 97552 122, which is about 17.78 mmHg lower than normal pressure.

The amount of air leakage that occurs in papermaking belts that function acceptably in the papermaking process is generally greater than about 40 barrels [about 2,000 cm 3 / min (NTP)] at an air permeability of 137 to 168 m 3 / min, which is preferred for air permeability. minimum range in the case of a composite belt. The belt air leakage reading should preferably be at least about 70 marlats [about 3,300 cm 3 / min (NTP)], and the belt air leakage reading should most preferably be at least about 100 marlats [about 4,500 cm 3 / min (NTP)] under the same conditions ( air permeability 137 - 168 m3 / min).

The backside texture of the desirable amount upper limit 15 is tekstuurimäärä, which allows the cross maximum amount of air to pass the papermaking belt 10. The backside 12 without the undesirable result that the suction pressure difference drops to less than that required to achieve the diversion of the papermaking belt of the paper web of the fibers 10 of the channels 20 36. It is believed that this the amount can be as high as 250 marlats [about 8400 cm3 / min (NTP)].

Figs. 34A to 34C are enlarged photographs of one example of a papermaking belt 10 made by the method of the present invention. The photographs of the belt shown in Figs. 34A to 34C 25 can be compared to the photographs of Figs. 33A and 33B of a previous smooth back belt.

A few points should be noted when looking at magnified photographs taken of these straps. First of all, it should be obvious that, due to the magnification ratio used, the parts of the straps shown in the photographs are generally very small parts of said slings. portions of the belts depicted in the photographs (and particularly the lengths of backside texturing) repre-35 is believed to moderate the characteristics of the entire belt. However, this does not mean that there are no parts of the belt that better represent the characteristics of the whole belt as a whole than the parts of the belts shown in the photographs.

5 Furthermore, it should be noted that the parts of the straps shown in the photographs are most likely not exactly the same as the parts of the straps shown in other photographs taken from different angles, as it is difficult to view and photograph the very small features of such a product when magnified. In other words, the belt parts which form the paper-contacting side 11 and backside 12 may not actually be directly on top of the belt 10. Likewise, the cross-section photographs of the belt may not represent cross-sections of the top and back sides of the photographs of the belt 15 parts. The following is a look at these enlarged photos of the straps with this in mind.

Figures 33A and 33B are top photographs, approximately 25 times the actual size, of the paper contacting side 11a and the backsheet 12a of the papermaking belt not disclosed herein. The belt shown in Figures 33A and 33B differs somewhat in size from the belts formed by the method of the present invention because the belt shown in Figures 33A and 33B is a belt with a linear Idaho pattern 711. The belt shown in Figures 33A and 33B therefore has smaller channels 36 and a greater number of channels per unit area. The belt 10a 30 shown in Figs. 33A and 33B is also different in that it has a single-layer structure.

The back side 12a of the belt 10a shown in Fig. 33B indicates one of the problems encountered in casting belts with smaller channels. Channels 36 had a tendency to close on the backing surface 12a. 33B 97 552 124 of the belt of Figure 10A, the backside 12a ideally should appear nearly identical to the Figure 33A by the paper-contacting side 11a. If the walls 44 of the channels 36 are inclined, the channels on the background surface 5 should appear smaller and the area of the background network should be larger. The deviation from the hypothetical ideal belt is also partly due to the slight imperfections of the belt, which proved to be greatly exaggerated in these ♦ photographs. When the back side 10 of the belt 10a shown in Fig. 1B is viewed under a microscope, the channel openings on the back side 12a of the belt 10a appear to be very similar to the channel openings on the paper-contacting side of the belt 10a. The belt 10a, however, this analysis shows that the channels 15 covered with a very thin film of resinous material, which may at least partially account for the differences backside 10a of the belt 12a appearance.

Figures 34A-34C are photographs of the belt 10 showing a belt 20 made by the method of the present invention having a linear Idaho pattern 300 and 35% of the knee surface. the belt shown in these figures, the backside texture formed by all the second warp layer D for the warp yarns 53 of first opacity 0l. The first opacity Oj was obtained on the warp yarns 53 of the second warp layer D by coating the individual yarns with an organic dye. The coating was done with a more specific black ink marking pen. All photos are magnified about 25 times the actual size of the strap. Figure 34A is a photograph of 30 in contact with the belt 10 of the paper side 11, taken at an angle of approximately 35 degrees in contact with the paper side surface of an imaginary normal (ie. In the direction of z) of the. Fig. 34B is a photograph of the back side 12 of the belt 10 shown in Fig. 34A. Fig. 97552 125 34C is a pedal sectional view of the belt 10 shown in Figs. 34A and 34B.

Figure 34A shows that the paper side network (which carries a pap *>. Rirainaa) is macroscopically yksita-5 swampy, patterned, and continuous. As Figure 34A shows that the paper side network 34a is also microscopically-one level, patterned and continuous magnification of the photograph was taken. The paper side network surface 34a surrounds and defines the openings 36 of the plurality of channels 42, 10 which channels the fibers in the embryonic web can be deflected and rearranged form of the improved paper web. The reinforcing structure 33 can be seen in the holes or openings 41 found by the channels 36. The reinforcing structure 33 consists of a plurality of machine direction warp yarns 53 interwoven with a plurality of transverse weft yarns 54 so as to leave pores 39 between them. 33 is a preferred multilayer reinforcing structure with vertically overlapping warp yarns 53. As shown in Figure 34A, the pores 39 are generally a few times 20 times smaller than the channels 36. The reinforcing structure 33 vents the grid 32 without disturbing the flow of water and the passage of air through the channels 36.

Figures 34B and 34C show the backside 10 of the belt 12. Figures 34B and 34C show the backside texturing 25 Nin, which is formed by the process of this invention. As shown in Figures 34B and 34C is shown the backside network 35a is discontinuous. The air generated by the method according to the present invention, the backside texturing the backside network 35a would appear very similar to the 30 paper side network.

Figure 34B produced by the method according to the present invention, the backside texturing comprises passageways 37 that provide surface texture irregularities 38 of the framework 32 in the backside network 35a. Purity-35 counterpart texture appears as a set of discontinuities in the background 126 97 552 side network 35a. These discontinuities comprise passageways 37. Passageways 37 are moderately regular and distributed according to the general pattern. The passageways 37 are located mainly on the warp yarns 53, which 5 form the first part P01 of the reinforcing structure 33 (i.e. with projections of the warp surfaces). When the first part P01 comprises the warp yarns 53 in the second warp layer D, the projection Ax of the first surface and the projection of the warp surface are the same.

10 Figure 34B also shows that, a plurality of passageways located near the machine side loimipolvekepintojen from projections and being close to the knuckles 105b2, which kudelan-yarns 54 form the reinforcing per 33 of the machine structure, on the side 52. This is believed to be due at least in 15 part in that the machine-side warp knuckles 105b2 comprise a part of the reinforcing structure which is in direct contact during the working surface of the forming unit during the casting process, and as a result there is no resin material between these knees and the working surface. This makes these knees feel exposed on the finished strap 10.

Figure 34C shows that the heights of the passageways 37 extend inward of the plane defined by the machine-facing side of the reinforcing structure Pk2 the first portion 25 of opaque-Poi group of the structural components 40a of the bottom side.

Although specific embodiments of the present invention have been illustrated and described, it should be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. The appended claims are therefore intended to cover all such changes and modifications as fall within the scope of the invention.

Claims (10)

A papermaking belt with a paper contacting side (11) and a back side (12) on the opposite sieve of the paper contacting saddle, wherein the pepper creamer belt (10) comprises a framework (32) of hardened, light sensitive resin material with a first surface (34) defining the paper contacting screen (11) of the belt (10), a second surface (35) on the opposite screen of the first surface, and channels 10 (36) extending between the first surface (34) and the the second surface (35), and a reinforcing structure (33) positioned between the first surface (34) and at least a portion of the second surface (35) of the frame (32), the reinforcing structure (33) having spaces (39). ) and a reinforcing component (40), characterized in that it has a textured back (12), that the first surface (34) of the frame (32) has a web (34a) located on the paper side, which defines the channels (36). ), and the second surface (35) has a web (35a) having a through genome threaded channels (37) which differ from the channels (36) and which form irregularities (38) in the surface texture of the web (35a) at the rear; that a first portion (Po1) of the gain component (40) has a first opacity (01) and a second portion (Po2) of the gain component (40) has a second opacity (02) which is lower than the first opacity (02). the site, the first opacity (02) being sufficient to substantially prevent curing of the photosensitive resin material forming the framework (32), where the photosensitive resin material is in its uncured state and the first portion (Po1) is positioned between the photosensitive resin material and an actinic light source (73), and the second opacity (02) is sufficient to allow curing of the photosensitive resin material, the first portion (Po1) defining a first projected area; and that the passage channels (37) in the network (35a) have been positioned at the back of the framework (32) in the predominant part 1 of the area projected. Paper making belt according to claim 1, characterized in that the reinforcing structure (33) comprises at least one structural component (40a) and the first portion (Po1) comprises at least one structural component, which at least partially comprises an opaque component. material, which is opaque to light with a path length of about 200 - 600 nanometers. The papermaking belt according to claim 1 or 2, characterized in that the reinforcing structure (33) comprises a woven element and the reinforcing component (40) comprises a plurality of structural components (40a), the structural components ( 40a) comprises a plurality of 1 machine-direction warp yarns (53) interwoven with a plurality of 1 machine transverse weft yarns (54) to form the gaps (39) between the warp yarns and the weft yarns, and that at least some of the warp yarns have the first the opacity (0X). 4. A papermaking belt according to claim 3, characterized in that the reinforcing structure (33) comprises a multi-layer woven element having a paper-facing side (51) and a machine-facing side (52) on the opposite side of the the paper facing side, and the warp yarn (53) in the machine direction has been placed in a first layer (C) and in a second layer (D), and the weft trees in the first and second layers are arranged in a substantially vertically stacked relationship to each other , wherein the first layer (C) of warp yarn (53) together with the interwoven weft trees (54) forms the paper-facing side (51) of the reinforcing structure (33), and the second layer (D) of warp yarn (53) together with the interwoven weft trees (54), the side (52) facing the machine forms the reinforcing structure (33), and that at least part of the warp yarn (53) in the second genus (D) has said first opacity -tea ten (0X). 5. A papermaking belt according to claim 1, characterized in that the first part (Po1) comprises an opaque coating (70), which is opaque for 1 juice with a path length of about 200-400 nanometers, and that the coating (70) is applied to the side (52) of the reinforcing structure (33) facing the machine. 10 A method of producing a papermaking frame, wherein the papermaking belt (10) comprises a reinforcing structure (33) and a frame (32) consisting of light-sensitive resin material and the framework (32) has a first surface (34), a second surface. (35) and channels (36), each extending between the first surface and the second surface, characterized in that the papermaking belt has textured backing (12), that the first surface (34) has a web-like web ( 34a), which defines the channels (36) and that the second surface (35) has a backed web (35a) with passage openings (37) which separate from the channels (36) and cause irregularities (38). the surface structure 1 of the backing web (35a), and the method comprising the following steps, when each (a) forms a forming unit (71) with a working surface (72); (b) blends a reinforcing structure (33) with a paper facing (51), a machine facing (52) on the opposite side of the paper facing side, space 30 (39) and a reinforcing component (40) which consists of a plurality of structural components (40a), wherein a first portion (Po1) of the reinforcing component (40) has a first opacity (0 *) and a second portion (Po2) of the reinforcing component (40) has a second opacity (02). ), which is lower than the first opacity, and the first opacity (0i) is sufficient to substantially prevent the curing of the photosensitive resin material where the photosensitive material exhibits 1 uncured state, and the first portion < Pol> is located between the light-sensitive resin material and an active light source (73), and the second opacity (02) is sufficient to allow curing of the light-sensitive resin material, the first part (Po1 ) defines a first projected area; 9 (c) at least a portion of the face (51) of the reinforcing structure (33) contacts the working surface (72) in the molding unit (71) at least a portion of the reinforcing structure (33); (d) applying a coating (70) of liquid, photosensitive resin to at least one side of the reinforcing structure (33) so that the coating (70) forms a first surface (34 *) and a second surface (35 *) »Wherein the cover (70) is distributed so that at least a portion of the second surface (35 ') of the cover will be adjacent to the working surface (72) of the molding unit (71) and portions of the other surface (35') will be between the first portion of the reinforcing component (40) and the working surface (72) of the molding unit (71), and the paper-facing side (51) of the reinforcing structure (33) being positioned between the first and second surfaces of the coating (70), the portion of the coating (70) lying between the first surface (34 ') of the coating and the paper-facing side (51) of the reinforcing structure (33) comprises a resin coating (tc, t0 *); (e) regulating the thickness of said cover (t0, t0 ') according to a predetermined value; (F) forming a mask (74) having opaque and transparent regions, the opaque regions (74a) together with the transparent regions (74b) defining a preselected pattern in the mask (74); (g) positioning the mask (74) between the coating (70) of liquid, photosensitive resin and an actinic light source 97552 137 (73) such that the mask (74) is in contact with the first surface (34 ') of the coating (70); the opaque regions (74a) of the mask (74) shielding a portion of the coating (70) against the light rays from the light source (73) and the transparent regions (74b) leaving other portions of the coating (70) unprotected ; (h) curing the unprotected portions of the liquid, photosensitive resin coating (70) and of such portions of the coating (70) as the second portion (Po2) of the reinforcing structure (33) to cure, leaving the shielded portions and such portions of the coating (70) between the first portion (Po1) of the reinforcing structure (33) and the working surface (72) of the forming part (71) uncured, by exposing the coating (70) of liquid, photosensitive resin for light having an activating path length from the light source (73) through the mask (74) and through the gain structure (33) to provide a partially formed composite band (10 '); and (i) removing substantially all uncured, liquid, photosensitive resin from the partially formed composite band (10 ') to accommodate a hardened resin framework (32) which has a plurality of channels (36) in such regions which are shielded from the light beams by means of the opaque regions (74a) of the mask (74), and passage channels (37), which provide irregularities (38) in the surface texture of the abutment (35a) attached to the back of the frame (32), which corresponds to lateral portions on the second surface (35 ') of the cover (70) prevented from curing through the first portion (Po1) of the reinforcing structure (33). 7. A papermaking belt with textured backing, characterized in that it is manufactured according to the method of claim 6. 8. A method of producing a strong, soft, absorbent web, characterized in that a (9) water dispersion (14) of papermaking fibers is formed; (b) forming an elementary web (18) of papermaking fibers from the dipper liner (14) on a permeable surface (15); (c) contacting the elementary web (18) with the paper contacting screen (51) of a papermaking belt (10) according to claims 1, 2, 3, 4 or 5; (d) drive the papermaking belt (10) and the elementary web (18) over a vacuum source (24a) and apply a fluid pressure differential to the elementary web (18) with the vacuum source (24a) si, the liquid pressure supply valve being applied from the rear 12) of the papermaking belt (10) through the channels (36) of the papermaking belt (10) to deflect at least part of the pepper frame along the longitudinal webs of the elemental web (18) into the channels (36) of the papermaking belt (10) and to remove water from the elemental web (18) through the channels (36), and rearrange the fibers 1 of the elemental web (18) to form an intermediate web (25) of the papermaking fibers under such conditions that the drain is initiated at the last of the initiation. of the drainage 1 the elementary web (18); (e) pressing the web (34a) located on the paper side into the intermediate web (25) by positioning the intermediate web between the papermaking belt (10) and an embossing surface, to form an embossed web (29) of papermaking fibers; and (f) drying the embossed web (29). 9. Strong, soft, absorbent paper, characterized in that it is produced by the method of claim 8. A papermaking fabric intended for use in a papermaking machine, which papermaking fabric comprises a multiplicity yarn, said multiplying yarn comprising a multiplicity of warp yarns (53) which are interwoven with a multiplicity of the interpulating yarns 54 , to form spaces (39) between them, characterized in that a portion of the yarn folded yarn has a first opacity (0Χ) and a portion of the yarn has a second opacity (02), and the first opacity is higher than the second opacity.